Devices and methods for the production of coaxial microfibers and nanofibers

ABSTRACT

Described herein are apparatuses and methods of creating fibers, such as microfibers and nanofibers. The methods discussed herein employ centrifugal forces to transform material into fibers. Apparatuses that may be used to create fibers are also described. Decsribed herein are fiber producing devices that are capable of producing coaxial fibers.

PRIORITY CLAIM

This application claims the benefit of U.S. Provisional Application No.61/440,219 filed on Feb. 7, 2011.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to the field of fiberproduction. More specifically, the invention relates to fibers of micronand sub-micron size diameters.

2. Description of the Relevant Art

Fibers having small diameters (e.g., micrometer (“micron”) to nanometer(“nano”)) are useful in a variety of fields from the clothing industryto military applications. For example, in the biomedical field, there isa strong interest in developing structures based on nanofibers thatprovide scaffolding for tissue growth to effectively support livingcells. In the textile field, there is a strong interest in nanofibersbecause the nanofibers have a high surface area per unit mass thatprovide light, but highly wear resistant, garments. As a class, carbonnanofibers are being used, for example, in reinforced composites, inheat management, and in reinforcement of elastomers. Many potentialapplications for small-diameter fibers are being developed as theability to manufacture and control their chemical and physicalproperties improves.

It is well known in fiber manufacturing to produce extremely finefibrous materials of organic fibers, such as described in U.S. Pat. Nos.4,043,331 and 4,044,404, where a fibrillar mat product is prepared byelectrostatically spinning an organic material and subsequentlycollecting spun fibers on a suitable surface; U.S. Pat. No. 4,266,918,where a controlled pressure is applied to a molten polymer which isemitted through an opening of an energy charged plate; and U.S. Pat. No.4,323,525, where a water soluble polymer is fed by a series of spacedsyringes into an electric field including an energy charged metalmandrel having an aluminum foil wrapper there around which may be coatedwith a PTFE (Teflon™) release agent. Attention is further directed toU.S. Pat. Nos. 4,044,404, 4,639,390, 4,657,743, 4,842,505, 5,522,879,6,106,913 and 6,111,590—all of which feature polymer nanofiberproduction arrangements.

Electrospinning is a major manufacturing method to make nanofibers.Examples of methods and machinery used for electrospinning can be found,for example, in the following U.S. Pat. Nos.: 6,616,435; 6,713,011;7,083,854; and 7,134,857.

SUMMARY OF THE INVENTION

Described herein are apparatuses and methods of creating fibers, such asmicrofibers and nanofibers. The methods discussed herein employcentrifugal forces to transform material into fibers. In one embodimenta fiber producing system includes a fiber producing device and a drivercapable of rotating the fiber producing device. The fiber producingdevice, in one embodiment, includes a body having one or more openingsand a coupling member, wherein the body is configured to receivematerial to be produced into a fiber; and one or more nozzles coupled toone or more of the openings, wherein the one or more nozzles comprise anozzle orifice. The body of the fiber producing device is couplable tothe driver through the coupling member. During use rotation of the fiberproducing device coupled to the driver causes material in the body to bepassed through one or more openings, into one or more nozzles, andejected through one or more nozzle orifices to produce microfibersand/or nanofibers. In some embodiments, fiber producing system may beconfigured to substantially simultaneously produce microfibers andnanofibers.

The nozzles of the fiber producing device, in one embodiment, areremovably couplable to the body. Alternatively, nozzles of the fiberproducing device may be an integral part of the body. A sealing ring maybe positioned between one or more of the nozzles and the body to helpmaintain a secure fitting between the nozzle and the body. In oneembodiment, the body includes a locking system used to couple one ormore nozzles to the openings, wherein the locking system locks thecoupled nozzles in a predetermined orientation with respect to the body.

A nozzle may be removably couplable to a fiber producing device.Alternatively, a nozzle may be formed on a sidewall of the body of thefiber producing device such that the body and nozzle are formed from asingle, unitary material. Alternatively, an opening extending throughthe sidewall may be formed at the junction of a pair of joined circularplates that have an alignment ring or pins. A nozzle may include anozzle body, the nozzle body defining an internal cavity and having aproximal end and a distal end, wherein the proximal end comprises acoupling portion that allows the nozzle to be coupled to a fiberproducing device. The coupling portion of the nozzle, may, in oneembodiment, be a threaded end which mates with a corresponding threadedportion of the fiber producing device. A nozzle tip may be coupled tothe distal end of the nozzle body, wherein the nozzle tip has aninternal diameter that is less than the internal diameter of the nozzlebody. The nozzle body includes an opening extending through a wall ofthe nozzle body, the nozzle tip being aligned with the nozzle openingsuch that material disposed in the nozzle body passes through theopening into the nozzle tip during use. The internal diameter of thenozzle tip may be set such that microfibers and/or nanofibers areproduced when material is ejected through the nozzle tip when the nozzleis coupled to a fiber producing device.

In an embodiment, the nozzle tip and the nozzle body are formed from asingle, unitary material. Alternatively, the nozzle tip may be removablycouplable to the nozzle body. A nozzle may have a length of at leastabout 2 mm. An internal diameter of the nozzle tip may be less thanabout 1 mm. A portion of the interior wall of the nozzle body issubstantially flat and another portion of the interior wall of thenozzle body is angled and/or rounded from the flat portion toward theopening formed in the nozzle body. In one embodiment, a nozzle tip mayhave an angled and/or rounded nozzle outlet end. A nozzle may have anon-cylindrical outer surface. In one embodiment, a nozzle has an outersurface having a tapered edge. During rotation of the body, gassescontact the tapered edge of the nozzle, creating a region of negativepressure on the side opposite to the tapered edge.

One or more outlet conduits may couple one or more nozzles to one ormore openings. Outlet conduits may have a length to help set thematerial diameter before ejection from the nozzle (e.g., from 1 mm toabout 10 mm, or about 2 mm to about 7 mm, or about 5 mm). Nozzles mayinclude a nozzle orifice.

The body of the fiber producing device comprises one or more sidewallsand a top together defining an internal cavity, wherein one or moreopenings extend through a sidewall of the body, communicating with theinternal cavity. In an embodiment, an interior surface of the sidewallis angled from a bottom wall toward one or more of the openings. In analternate embodiment, an interior surface of the sidewall is roundedfrom a bottom wall toward one or more of the openings. An interiorsurface of the sidewall may have an oval shape such that the long axisof the oval interior sidewall is in alignment with one or more of theopenings.

The driver may be positioned below the fiber producing device or abovethe fiber producing device, when the fiber producing device is coupledto the driver. The driver may be capable of rotating the fiber producingdevice at speeds of greater than about 1000 RPM

In one embodiment, a heating device is thermally coupled to the fiberproducing device. In an embodiment, a fluid level sensor is coupled tothe fiber producing device, the fluid level sensor being positioned todetect a level of fluid inside the fiber producing device.

The fiber producing device may be enclosed in a chamber, wherein theenvironment inside the chamber is controllable. A fiber producing systemmay include a collection system surrounding at least a portion of thefiber producing device, wherein fibers produced during use are at leastpartially collected on the collection system. The collection system, inone embodiment, includes one or more collection elements coupled to acollection substrate, wherein the one or more collection elements atleast partially surround the fiber producing device. In one embodiment,the collection elements comprise an arcuate or straight projectionextending from the collection substrate surface.

In another embodiment a fiber producing system includes a fiberproducing device and a driver capable of rotating the fiber producingdevice. The fiber producing device, in one embodiment, includes a bodyhaving one or more openings and a coupling member, wherein the body isconfigured to receive material to be produced into a fiber; and one ormore needle ports coupled to one or more of the openings, wherein one ormore needles are removably couplable to the needle ports during use. Thebody of the fiber producing device is couplable to the driver throughthe coupling member. During use rotation of the fiber producing devicecoupled to the driver causes material in the body to be ejected throughone or more needles coupled to one or more needle ports to producemicrofibers and/or nanofibers. In one embodiment, needles coupled to theone or more needle ports have an angled and/or rounded outlet.

In another embodiment a fiber producing system includes a fiberproducing device and a driver capable of rotating the fiber producingdevice. The fiber producing device, in one embodiment, includes a bodycomprising two or more chambers and a coupling member, wherein a firstchamber comprises one or more openings and is configured to receivematerial to be produced into a fiber; and wherein a second chambercomprises one or more openings and is configured to receive material tobe produced into a fiber. The body of the fiber producing device iscouplable to the driver through the coupling member. During use,rotation of the fiber producing device coupled to the driver causesmaterial in at least the first chamber and the second chamber to beejected through the one or more openings to produce microfibers and/ornanofibers.

In another embodiment a fiber producing system includes a fiberproducing device and a driver capable of rotating the fiber producingdevice. The fiber producing device, in one embodiment, includes a bodycomprising one or more openings and a coupling member, wherein the bodyis configured to receive material to be produced into a fiber. The bodyof the fiber producing device is couplable to the driver through thecoupling member. The fiber producing system further includes acollection system that collects fibers produced by the fiber producingdevice during use, the collection system comprising one or morecollecting elements coupled to a collection element substrate, whereinone or more collection elements comprise an arcuate projection extendingfrom the collection element substrate. During use, rotation of the bodycoupled to the driver causes material in the body to be ejected throughone or more openings to produce microfibers and/or nanofibers that areat least partially collected on the collecting elements.

In an embodiment, a collection system of a fiber producing systemincludes one or more collecting elements coupled to a collection elementsubstrate, wherein the collection elements are positioned surrounding atleast a portion of the fiber producing device, and wherein the positionof the collection elements with respect to the fiber producing device isadjustable by moving the collection elements along a portion of thecollection element substrate.

In another embodiment, a collection system of a fiber producing systemincludes one or more collecting elements coupled to a collection elementsubstrate and a collection container, wherein the collection containerat least partially surrounds the fiber producing device and wherein thecollection elements are removably positionable in the collectioncontainer.

In another embodiment, a collection system of a fiber producing deviceis configured to collect fibers produced by the fiber producing device.During use rotation of the fiber producing device causes material in thebody to be ejected through one or more openings to produce microfibersand/or nanofibers. The collection system produces a vacuum or activateda gas flow device that causes a flow of produced fibers to thecollection system.

In another embodiment a fiber producing system includes a fiberproducing device and a driver capable of rotating the fiber producingdevice. The fiber producing device, in one embodiment, includes a bodycomprising one or more openings and a coupling member, wherein the bodyis configured to receive material to be produced into a fiber. The bodyof the fiber producing device is couplable to the driver through thecoupling member. The fiber producing system further includes adeposition system that collects fibers produced by the fiber producingdevice during use and directs the collected fibers toward a substratedisposed in the deposition system during use. During use, rotation ofthe body coupled to the driver causes material in the body to be ejectedthrough one or more openings to produce microfibers and/or nanofibersthat are at least partially transferred to the deposition system.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the present invention will become apparent to thoseskilled in the art with the benefit of the following detaileddescription of embodiments and upon reference to the accompanyingdrawings in which:

FIG. 1A depicts a perspective view of an embodiment of a fiber producingdevice that includes peripheral openings;

FIG. 1B depicts a cross-sectional side view of an embodiment of a fiberproducing device that includes peripheral openings;

FIG. 2 depicts one or more nozzles coupled to one or more openings of afiber producing device;

FIG. 3 shows a cross-sectional view of the fiber producing device ofFIG. 2;

FIG. 4 shows a removably coupleable nozzle, needle port and needle thathave been removed from a fiber producing device;

FIG. 5 depicts a cross section view of an embodiment of a nozzle that iscouplable to a fiber producing device;

FIG. 6 depicts a cross-sectional top view of a fiber producing device;

FIG. 7A depicts an alternate embodiment of a fiber producing device;

FIG. 7B depicts cross-section view of an alternate embodiment of a fiberproducing device;

FIG. 8 depicts an embodiment of a removably couplable outlet conduit;

FIG. 9A and 9B depict cross-sectional views of embodiments of a couplingportion of an opening in a body of a fiber producing device;

FIGS. 10A and 10B depict cross-section end views of embodiments ofnozzles having a non-cylindrical profile;

FIGS. 11A-11F depict various outlet configurations for nozzle tips andneedle ends;

FIGS. 12A and 12B depict embodiments locking systems for a needle;

FIGS. 13A-13C depict embodiments of locking systems for a nozzle;

FIGS. 14A and 14B depict alternate embodiments of locking systems forneedles;

FIGS. 15A and 15B depict an alternate embodiment of a fiber producingdevice;

FIG. 16 depicts an alternate embodiment of a fiber producing device;

FIGS. 17A-17D depict examples of multiple level fiber producing device;

FIG. 18 depicts a multiple level fiber producing system having amaterial feed inlet;

FIG. 19 depicts a fiber producing device having a circular supportmember;

FIGS. 20A and 20B depict a top view of a fiber producing system thatincludes a fiber producing device and a collection wall;

FIG. 21A depicts an embodiment of a collection system having projectingcollection elements;

FIG. 21B depicts an embodiment of a collection system having arcuatecollection elements;

FIGS. 22A and 22B depict an alternate embodiment of a collection system;

FIGS. 23A-23C depict embodiments of a collection system having removablecollection substrates;

FIG. 24 depicts an embodiment of a diversion device coupled to acollection system;

FIG. 25 depicts a fiber producing system disposed in a housing;

FIG. 26 depicts a fiber producing system having a gas flow collectionsystem;

FIG. 27 depicts a fiber producing system having a vacuum collectionsystem;

FIG. 28 depicts a fiber producing system with a driver mounted above thefiber producing device;

FIG. 29 depicts an embodiment of a portion of fiber producing systemconfigured for deposition of fibers on a substrate;

FIG. 30 depicts an embodiment of a fiber producing system configured forcontinuous deposition of fibers on a substrate;

FIG. 31 depicts an embodiment of a purge system coupled to a fiberproducing device;

FIG. 32 depicts a coaxial outlet element;

FIG. 33 depicts an inverted fiber producing system having a continuousliquid mixture feed;

FIG. 34 depicts an inverted fiber producing device having a continuousmelt feed;

FIG. 35 depicts a substrate deposition system;

FIG. 36 depicts a fiber deposition system;

FIG. 37 depicts a deposition system that includes multiple fiberproducing devices;

FIGS. 38A-D depict an embodiment of a fiber producing device;

FIG. 39 depicts an embodiment of a heating device;

FIG. 40 depicts an alternate embodiment of a fiber producing device;

FIG. 41 a-b depict a star shaped fiber producing device; and

FIG. 42 depicts a gear shaped fiber producing device.

While the invention may be susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and will herein be described in detail. Thedrawings may not be to scale. It should be understood, however, that thedrawings and detailed description thereto are not intended to limit theinvention to the particular form disclosed, but to the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the present invention as definedby the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It is to be understood the present invention is not limited toparticular devices or methods, which may, of course, vary. It is also tobe understood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting. As used in this specification and the appended claims, thesingular forms “a”, “an”, and “the” include singular and pluralreferents unless the content clearly dictates otherwise. Furthermore,the word “may” is used throughout this application in a permissive sense(i.e., having the potential to, being able to), not in a mandatory sense(i.e., must). The term “include,” and derivations thereof, mean“including, but not limited to.” The term “coupled” means directly orindirectly connected.

The terms “comprise” (and any form of comprise, such as “comprises” and“comprising”), “have” (and any form of have, such as “has” and“having”), “include” (and any form of include, such as “includes” and“including”) and “contain” (and any form of contain, such as “contains”and “containing”) are open-ended linking verbs. As a method or apparatusthat “comprises,” “has,” “includes” or “contains” one or more steps orelements possesses those one or more steps or elements, but is notlimited to possessing only those one or more steps or elements Likewise,an element of an apparatus that “comprises,” “has,” “includes” or“contains” one or more features possesses those one or more features,but is not limited to possessing only those one or more features.

Described herein are apparatuses and methods of creating fibers, such asmicrofibers and nanofibers. The methods discussed herein employcentrifugal forces to transform material into fibers. Apparatuses thatmay be used to create fibers are also described. Some details regardingcreating fibers using centrifugal forces may be found in the followingU.S. Published Patent Applications: 2009/0280325 entitled “Methods andApparatuses for Making Superfine Fibers” to Lozano et al.; 2009/0269429entitled “Superfine Fiber Creating Spinneret and Uses Thereof” to Lozanoet al.; 2009/0232920 entitled “Superfine Fiber Creating Spinneret andUses Thereof” to Lozano et al.; and 2009/0280207 entitled “SuperfineFiber Creating Spinneret and Uses Thereof” to Lozano et al., all ofwhich are incorporated herein by reference.

One embodiment of a fiber producing device is shown in FIG. 1A. Fiberproducing device 100 includes a top 110 that is coupled to body 120.Body 120 acts as a reservoir which holds material to be spun intofibers. Top 110 has an opening 112 to allow introduction of material tobe spun. For this type of fiber producing device, typical amounts ofmaterial range from 50-100 mL, but amounts less than this may be used aswell as amounts greater than this, as the size of the reservoir and thefiber producing device may each vary. Body 120 includes one or moreopenings 122. A coupling member 160 is coupled to the body. Couplingmember 160 may be used to couple fiber producing device 100 to a driverthat is capable of rotating the fiber producing device. Coupling member160 may be an elongated member extending from the body which may becoupled to a portion of the driver (e.g., a chuck or a universalthreaded joint of the driver). Alternatively, coupling member may be areceiver which will accept an elongated member from a driver (e.g., thecoupling member may be a chuck or a universal threaded joint). Suitabledrivers include commercially available variable electric motors, such asa brushless DC motor.

During use, rotation of the fiber producing device causes material to beejected through one or more openings 122 to produce fibers. In someembodiments, openings 122 may have a size and/or shape that causes thecreation of microfibers and/or nanofibers as the material is ejectedthrough the openings.

FIG. 1B depicts a cross-sectional side view of an embodiment of fiberproducing device 100. Body 120 of fiber producing device 100 may furtherinclude a tip 124 coupled to one or more openings 122. Body 120 alsodefines an internal cavity 140 from which material flows toward openings122 and, optionally, through tip 124. In some embodiments, tip 124 hasan internal diameter that is less than the diameter of the opening. Tip124 is coupled to an opening 122 formed in a wall of body 120 such thatthe tip is substantially aligned with opening. Thus, material disposedin internal cavity 140 passes through opening 122 and through tip 124when exiting fiber producing device 100. The internal diameter and/orshape of tip 124 is selected such that microfibers and/or nanofibers areproduced when the material is ejected from body 120 of a spinning fiberproducing device through the tip. Tip 124 may be removably coupled tobody 120. Alternatively, tip 124 and body 120 are formed from a single,unitary material such that the tip is not removable from the body, butinstead is an integral part of the body.

In an embodiment depicted in FIG. 2, one or more nozzles 130 may becoupled to one or more openings 122 of fiber producing device 100. Asused herein a “nozzle” is a mechanical device designed to control thedirection or characteristics of a fluid flow as it exits (or enters) anenclosed chamber or pipe via an orifice. Nozzles may have an internalcavity 138 running through the longitudinal length of the nozzle, asdepicted in FIG. 3. Internal cavity 138 may be substantially alignedwith opening 122 when nozzle 130 is coupled to an opening. Spinning offiber producing device 100 causes material to pass thorough one or moreof openings 122 and into one or more nozzles 130. The material is thenejected from one or more nozzles 130 through nozzle orifice 136 toproduce fibers. Nozzle 130 may include a nozzle tip 134 having aninternal diameter smaller than an internal diameter of nozzle internalcavity 138. In some embodiments, internal cavity 138 of nozzle 130and/or nozzle orifice 136 may have a size and/or shape that causes thecreation of microfibers and/or nanofibers by ejecting of the materialthrough the nozzle.

It should be understood that while opposing openings are depicted, theopenings may be placed in any position on the body of a fiber producingdevice. The position of the openings may be varied to create differentkinds of fibers. In some embodiments, openings may be placed indifferent planes of the fiber producing device. In other embodiments,openings may be clustered in certain locations. Such alternatepositioning of the openings may increase the fiber dispersion patternsand/or increase the fiber production rates. In some embodiments, theopenings, regardless of the position, may accept an outlet element(e.g., a nozzle or needle).

FIG. 3 shows a cross-sectional view of fiber producing device of FIG. 2.Body 120 includes one or more sidewalls 121 and a bottom 123 whichtogether define an internal cavity 125. In one embodiment, body 120 issubstantially circular or oval and includes a singular continuoussidewall 121, for example, sidewall and bottom are a single, unitarycomponent of the fiber producing device. Openings 122 are formed insidewall 121 of body 120, extending through the sidewall such that theopening allows transfer of material from internal cavity 125 through thesidewall. In an embodiment, sidewall 121 is angled from bottom 123toward one or more openings 122. Alternatively, sidewall 121 may berounded from bottom 123 toward one or more openings 122. Having anangled or rounded sidewall extending toward one or more openingsfacilitates flow of material in the body toward the openings when thefiber producing device is being rotated. As the fiber producing deviceis rotated the material rides up the angled or rounded walls toward theopenings. This minimizes the occurrence of regions where material isinhibited from traveling toward the openings.

In an embodiment, nozzle(s) 130 may be removably coupled to body 120.For example, nozzle 130 may include a nozzle coupling portion 132 whichis couplable to a corresponding coupling portion 127 of one or more ofopenings 122. FIG. 4 shows a removably coupleable nozzle 130 that hasbeen removed from fiber producing device 100. In this embodiment, nozzle130 includes a threaded coupling portion 132, which has threading thatmatches threading 127 formed in opening 122. Nozzle 130 may be coupledto body 120 by fastening threaded coupling portion 132 onto threading127 of opening 122. Removably coupling a nozzle to a fiber producingdevice allows removal of the nozzles allowing the ability to customizethe production of fibers by allowing the outlet parameters to be changedby changing the nozzle. Additionally clean up of the fiber producingdevice is improved by allowing the nozzle to be removed and separatelycleaned.

FIG. 5 depicts a cross section view of an embodiment of a nozzle 130that is couplable to a body of a fiber producing device. Nozzle 130includes a nozzle body 131 having a proximal end 133 and a distal end135. Proximal end 133 includes a coupling portion 132 that allows nozzle130 to be coupled to the body of a fiber producing device. Couplingportion 132 may include a threaded portion which has threading thatmatches threading formed in an opening of a fiber producing device.

Nozzle 130 further includes a nozzle tip 134 coupled to distal end 135of the nozzle. Nozzle body 131 defines an internal cavity 138 throughwhich material flows from the body of a fiber producing device towardnozzle orifice 136. In some embodiments, nozzle tip 134 has an internaldiameter that is less than the diameter of internal cavity 138. Nozzletip 134 is coupled to an opening 139 formed in a wall of nozzle body131. Nozzle tip 134 is aligned with opening 139 such that materialdisposed in internal cavity 138 passes through opening 139 into thenozzle tip. The internal diameter and/or shape of nozzle tip 134 isselected such that microfibers and/or nanofibers are produced when thematerial is ejected form the body of a spinning fiber producing devicethrough the nozzle.

Nozzle tip 134 may be removably coupled to nozzle body 131.Alternatively, nozzle tip 134 and nozzle body 131 are formed from asingle, unitary material such that the nozzle tip is not removable fromthe nozzle body, but instead is an integral part of the nozzle body.Nozzle tip may be angled with respect to nozzle body. In someembodiments, nozzle 130 has a length of at least about 10 mm. In someembodiments, nozzle 130 has a length of between about 5 mm to about 15mm. An internal diameter of nozzle 130 may range from about 1.0 mm toabout 1 mm, depending on the size of fibers to be produced and theviscosity of the material being used to produce the fibers.

To facilitate transfer of material through nozzle 130, a portion ofnozzle body 131 may be angled or rounded toward opening 139. Forexample, distal portion 135 of nozzle body 131 may be angled from a flatportion of the nozzle body toward opening 139. Alternatively, distalportion 135 of nozzle body 131 may be rounded, as depicted in FIG. 5,from a flat portion of the nozzle body toward opening 139.

In another embodiment, a needle port 140 may be coupled to an opening122 of body 120. FIG. 4 depicts an embodiment of a removably couplableneedle port that has been removed from fiber producing device 100.Needle port 140 may include a coupling portion 142 and a needlereceiving portion 144. Needle receiving portion 144 may be used toremovably couple a needle to needle port 140. Coupling portion 142 ofneedle port 140 is couplable to a corresponding coupling portion 127 ofone or more of openings 122. For example, needle port 140 may include athreaded coupling portion 142, which has threading that matchesthreading 127 formed in opening 122. Needle port 140 may be coupled tobody 120 by fastening the threaded coupling portion 142 of the needleport onto threading 127 of opening 122. Removably coupling a needle portto a fiber producing device allows easy removal of the needle port forclean up. Needle ports offer an additional advantage of allowingcustomization of the fiber producing device by allowing needles to beremovably coupled to the fiber producing device.

In another embodiment, a needle 150 may be coupled to an opening 122 ofbody 120. FIG. 4 depicts an embodiment of a removably couplable needlethat has been removed from fiber producing device 100. Needle 150 mayinclude a coupling portion 152. Coupling portion 152 of needle port 150is couplable to a corresponding coupling portion 127 of one or more ofopenings 122. For example, needle 150 may include a threaded couplingportion 152, which has threading that matches threading 127 formed inopening 122. Needle 150 may be coupled to body 120 by fastening thethreaded coupling portion 152 of the needle onto threading 127 ofopening 122. Removably coupling a needle to a fiber producing deviceallows easy removal of the needle for clean up. Having a coupling formedon a needle ports offer an additional advantage of allowingcustomization of the fiber producing device by allowing needles to beremovably coupled to the fiber producing device.

FIG. 6 depicts a cross-sectional top view of fiber producing device 100.To further facilitate transfer of material, fiber producing device 100may have a substantially oval internal cavity 125. For example, sidewall121 may define an internal cavity 125 having a substantially ovalcross-sectional shape. The oval internal cavity has a long axis 610 anda short axis 620. Long axis 610 of internal cavity 125 may be alignedwith one or more openings 122. While internal cavity 125 has asubstantially oval shape, the external shape of body may besubstantially circular. This may be accomplished by varying the sidewallwidth to create an oval internal cavity while maintaining a circularexternal surface 630 of the body. As shown in FIG. 6, sidewall thickness“x” along the short axis 620 may be larger than the sidewall thickness“y” along long axis 610. This creates an oval shape for internal cavity125 while maintaining a circular external surface 630. Having an ovalinternal cavity helps to drive the material along the long axis of theoval when the fiber producing device is spinning. When the long axis isaligned with one or more openings, the material is thus directed to theopenings, helping to minimize waste and ensure a continuous flow ofmaterial through the openings.

An alternate embodiment of a fiber producing device is shown in FIG. 7A.Fiber producing device 200 includes a top 210 that is coupled to body220. Body 220 acts as a reservoir which holds material to be spun intofibers. Top 210 has an opening 212 to allow introduction of material tobe spun while the top is fastened to body 220. Alternatively, top 210may be removed from body 220 and the material added to the body prior tofastening the top to the body. Body 220 includes one or more openings222 and a coupling member 260 coupled to the body. Coupling member 260may be used to couple fiber producing device 200 to a driver that iscapable of rotating the fiber producing device. Coupling member 260 maybe an elongated member extending from the body which may be coupled to aportion of the driver (e.g., a chuck or a universal threaded joint ofthe driver). Alternatively, coupling member may be a receiver which willaccept an elongated member from a driver (e.g., the coupling member maybe a chuck or a universal threaded joint).

One or more needle ports 240 may be coupled to one or more openings 222via one or more outlet conduits 270. Outlet conduits 270 may have anannular passageway 272 extending through the longitudinal length of theoutlet conduit, as depicted in cross section view FIG. 7B. Outletconduit 270 may have a length of at least about 10 mm, at least about 20mm, at least about 30 mm, at least about 40 mm, at least about 50 mm, atleast about 60 mm inches, or at least about 70 mm. Outlet conduit 270may have a length of between about 10 mm to about 250 mm, at least about20 mm to about 200 mm, or at least about 30 mm to about 150 mm.

When material is ejected from an opening during spinning of a fiberproducing body, the material tends to expand as it leaves an opening. Ithas been found that by “setting” the diameter of the material prior tothe material exiting the fiber producing device, expansion of thematerial as it leaves the fiber producing device may be minimized. To“set” the diameter of the material annular passageway 272 may have asubstantially constant diameter. In some embodiments, the annularpassage has a constant diameter of between about 4 mm and about 30 mmover a length of about 10 mm to about 250 mm. Holding the material at aconstant diameter over a predetermined length, sets the diameter of thematerial, reducing the expansion of the material as it exits the outletconduit and nozzle. Reduction of swelling helps to improve theconsistency of the produced fibers with regard to size and length. Thelength and/or diameter of annular passage 272 may be selected based, atleast in part, on the type of material being used. Generally, as theviscosity of the material increases, a longer conduit may be used toproperly set the diameter of the material before the material exits thefiber producing device.

In an embodiment, outlet conduits 270 may be removably coupled to body220. FIG. 8 depicts an embodiment of a removably couplable outletconduit 270. Outlet conduit 270 may include a first coupling portion 274which is couplable to a complementary coupling portion 227 of a body 220and a second coupling portion 276 couplable to an outlet element 280. Anoutlet element, as used herein includes, but is not limited to, anozzle, a needle port, a needle or a combination of an outlet conduitcoupled to a nozzle, needle port or needle. Outlet element 280 includesa complementary coupling portion 282, which is couplable to secondcoupling portion 276 of outlet conduit 270. An outlet element 280 may becoupled to outlet conduit 270 by mating second coupling portion 276 ofthe outlet conduit onto coupling portion 282 of the outlet element.Removably coupling an outlet conduit to a body allows easy removal ofoutlet conduits. Having removably coupled outlet conduits improves theability to customize the production of fibers by allowing the outletparameters to be changed by changing the outlet conduit length anddiameter as well and the outlet element that is coupled to the outletconduit. Additionally clean up of the fiber producing device is improvedby allowing the outlet conduit to be removed and separately cleaned.Outlet elements such as nozzle 130, needle port 140 and needle 150, asdepicted in FIG. 4, may be coupled to second coupling portion 276 ofoutlet conduit 270.

FIG. 9A depicts a cross-sectional view of a coupling portion 310 of anopening in a body 300 of a fiber producing device. Coupling portion 310depicted in FIG. 9A may be used to couple a nozzle, a needle, a needleport, or an outlet conduit to body 300 of a fiber producing device.Coupling portion 310 includes, in one embodiment, threading 312 thatcouples with threading 322 of a removably couplable outlet element 320(e.g., a nozzle, a needle, a needle port, or an outlet conduit). In oneembodiment, threading 312 is formed on an interior wall of opening 302.Outlet element 320 includes threading 322 that is complementary to thethreading on coupling portion 310 of opening 302 to allow coupling ofthe outlet element to the body. A seal 350 (e.g., an o-ring) may bepositioned between outlet element 320 and body 300 to form a sealbetween the body and the outlet element.

An alternate embodiment of a coupling portion 310 of a body 300 of afiber producing device is depicted in the cross-section drawing depictedin FIG. 9B. In an embodiment, coupling portion 310 includes a couplingmember 340 formed proximate to an opening 302 formed in a sidewall ofbody 300. Coupling member 340 may protrude from opening 302. Couplingmember 340 includes, in one embodiment, threading 314 formed on anexternal surface of the coupling member that couples with threading 324of a removably couplable outlet element 320 (e.g., a nozzle, a needle, aneedle port, or an outlet conduit). A seal 350 (e.g., an o-ring) may bepositioned between outlet element 320 and body 300 to form a sealbetween the body and the outlet element.

In an embodiment, one or more nozzles may be coupled to the body of afiber producing device. During use material in the fiber producingdevice passes through the one or more nozzles and is ejected from theone or more nozzles to produce microfibers and/or nanofibers. Inembodiments where the nozzles protrude from the body of a fiberproducing device, the nozzles may be cooled by air striking the nozzleas the body is rotated. During a process in which a heated material isused, the cooling of the nozzles may cause the material passing throughthe nozzle to be cooled prior to exiting the nozzle. This cooling maycause inconsistent fiber production as the material properties (e.g.,viscosity) change as the material is cooled. To minimize the coolingeffect of air on the nozzles, the nozzles may be formed to have anon-cylindrical profile. FIGS. 10A and 10B depict cross-section endviews of embodiments of nozzles having a non-cylindrical profile. In theembodiment shown in FIG. 10A, a nozzle 410 has an outer surface havingtapered edge 412. Nozzle 410 is positioned on a body of a fiberproducing device such that the nozzle is rotated in a direction leadingwith tapered edge 412 (in FIG. 10A this would be in a direction right toleft or clockwise). Air 414 flows around the tapered edge creating aregion of negative pressure 416 around orifice 418 of nozzle 410. Regionof negative pressure 416 is believed to slow down the heat transfer fromthe nozzle to the air. Having a tapered leading edge may also reduce thedisruption of air flow on fiber forming as the material exits thenozzle.

FIG. 10B depicts an alternate embodiment of a non-cylindrical nozzle. Inthe embodiment shown in FIG. 10B, a nozzle 420 has an outer surfacehaving tapered leading edge 422 and a tapered trailing edge 423. Nozzle420 is positioned on a body of a fiber producing device such that thenozzle is rotated in a direction leading with leading edge 422 (in FIG.10B this would be in a direction right to left or clockwise). Air 424flows around the tapered edge creating a region of negative pressure 426around orifice 428 of nozzle 410. Region of negative pressure 426 isbelieved to slow down the heat transfer from the nozzle to the air andreduce the disruption of gas flow on fiber forming as the material exitsthe nozzle.

The end of a nozzle, a nozzle tip, and the end of a needle coupled to afiber producing device may be angled or rounded to alter the fiber sizeand configuration. Examples of various outlets configurations that maybe used for both nozzle tips and needle ends are shown in FIGS. 11A-11F.In each of the figures the downward pointing arrow indicates thedirection of gas flow across the end of the nozzle tip/needle end. InFIG. 11A, a nozzle tip or needle end has a flat end. A variation of thenozzle tip or needle end which may be used to alter the properties ofthe fiber produced include an angled nozzle tip or needle end, asdepicted in FIG. 11B, or various rounded nozzle tip or needle endconfigurations, as depicted in FIGS. 11C-11E. By changing the angle andconfiguration of a nozzle tip or needle end the material may be drawninto different fibers. In configuration 11F, a slight indentation isformed in nozzle tip or needle end to produce a region of reducedpressure at the end of the needle, facilitating production of fibers.

It has been further discovered that alterations in the angle of thenozzle or needle with respect to the body may also influence theproperties of the produced fibers. For example, as depicted in thefigures, nozzles and/or needles are typically positioned substantiallyperpendicular to the body. In some embodiments, nozzles or needles maybe placed at an angle deviating from perpendicular by any amount. Insome embodiments, the nozzle or needle may be placed on the body at anangle deviating from between about 1 to about 15 from perpendicular.

Production of desired fibers may therefore be controlled by the type ofnozzle or needle used, the orientation of the nozzle or needle withrespect to the direction of rotation, the nozzle tip or needle endconfiguration, and the angle of the nozzle or needle with respect to thebody. In order to facilitate proper placement of the nozzle or needle onthe body, different locking systems may be used. FIG. 12A shows alocking system that may be used for a needle. Needle 500 includes aprotrusion 510 at the coupling end of needle 500. An opening 520, thatthe needle is to be coupled with, has a complementary shape to theprotrusion at the end of needle 500. During use, needle 500 may only beinserted into opening 520 in the specific orientation that allowsprotrusion 510 to be inserted into the opening. A locking screw (notshown) may be used to lock needle 500 in place once the needle isproperly inserted in opening 520. In this manner, the needle may beplaced in the proper orientation without the user having to check forproper positioning of the needle. For example, if the tip of the needlehas a specific configuration, (e.g., as depicted in FIGS. 11B-11F), theuse of a locking system may ensure that the needle tip is in the properorientation with respect to the rotation of the body.

An alternate embodiment of a needle locking system is shown in FIG. 12B.Locking system 540 may include a plurality of angled protrusions 545arranged in a circle and extending from a locking member. Needlecoupling end 530 may also include a similar pattern of angledprotrusions that will complement the protrusions on locking system 540.During use, needle coupling end may be mated with the protrusions oflocking system 540 in a predetermined number of discrete positions. Whenplaced in the desired position the needle may be locked in place usingthe locking system. In an embodiment, a locking screw (not shown) may beused to lock the needle in place once the needle is properly positioned.In alternate embodiments, a clamp or clamping mechanism may be used tosecure the needle coupling portion to the locking system. In thismanner, the needle may be ensured to be placed in a selected discretethe proper orientation. Locking system 540 further offers the additionalfeature of allowing the needle to be placed in discrete, predeterminedpositions with respect to the body

Nozzles may also be coupled to a body through a locking system thatpositions the nozzle in a predetermined orientation. An embodiment of alocking system for a nozzle is depicted in FIGS. 13A and 13B. In thisembodiment, a nozzle 600 may include a coupling portion 610. Nozzle 600may be couplable to an opening 620 by sliding the nozzle couplingportion 610 into opening 620, in contrast to previous embodiments inwhich the nozzle included a threaded coupling portion. Coupling portion610 of nozzle 600 has a flat portion 612 which is matched with acorresponding flat portion 622 of an opening. The requirement to matchthe flat portion of the nozzle coupling end with a flat portion of theopening ensures that the nozzle is placed in the proper orientation. Aseal 630 (e.g., an o-ring) may be positioned between the nozzle and thebody to form a seal. To secure nozzle 600 in opening 620, a set screw635 may be used. In an embodiment, depicted in FIG. 13B, set screw 635may extend through body 640 of a fiber producing device and contact theflat portion of the coupling portion 610 of nozzle 600 to secure thenozzle in the opening. Alternatively, the set screw may engage thenozzle coupling end at an angle extending through the sidewall of thebody.

An alternate embodiment of a locking system for a nozzle is depicted inFIG. 13C. In this embodiment, a nozzle 600 may have a coupling end thatincludes one or more protrusions 652. Locking system includes one ormore recess 662 which can be matched with one or more protrusions 652 ofnozzle 600 to lock the nozzle in a predetermined position. Therequirement to match protrusions 652 of nozzle 600 with recesses 662ensures that the nozzle is placed in the proper orientation. A seal 650(e.g., an o-ring) may be positioned between nozzle 600 and body to forma seal between the body and the nozzle. To secure the nozzle in theopening, a set screw 635 may be used. In an embodiment, set screw 635may extend through the body, contacting the coupling end of nozzle tosecure the nozzle in the opening.

An embodiment of a locking system for a needle is depicted in FIG. 14A.A needle is couplable to an opening 710 of the body of a fiber producingdevice. Needle 700 includes a coupling portion 702 that includes a base704 and a seal 708 positioned around at least a portion of the base. Anindentation 707 may be formed in base 704. To secure needle 700 in theopening, a set screw 720 may be used. Set screw 720 may extend throughthe body of a fiber producing device and contact indentation 707 formedin base 704 of needle 700 to secure the needle in opening 710.Alternatively, the set screw may engage the indentation of the needle atan angle extending through the sidewall of the body. The formation of anindentation on the needle base helps secure the needle in the openingand helps a user to align the needle in the proper orientation. Seal 708(e.g., an o-ring) helps to form a seal between the base and the opening.

Another embodiment of a locking system for a needle is depicted in FIG.14B and FIG. 14C. In this embodiment, a needle 700 is couplable to anopening of the body of a fiber producing device. Needle 700 includes acoupling portion 730 that includes base 732 and a locking tab 734protruding from the base. An opening of the body of a fiber producingdevice, or a needle port, may have a locking system capable of securingneedle 700. An example of a locking system 740 is depicted in FIG. 14C.Locking system 740 includes an indentation 742 that receives locking tab734 and a portion of base 732. To secure the needle in an opening,needle 700 is oriented such that locking tab 734 is aligned withindentation 742 of locking system 740. Once locking tab 734 is insertedinto indentation 742, base 732 can be turned to secure locking tab 734under a portion 744 of locking system 740. A set screw may be used tosecure the needle in the locking system. In some embodiments, a setscrew may not be needed. Base 732 may include one or more seals 736.Seals 736 may provide a secure fitting between a portion of base 732 andthe surface of the body or needle port. When in contact with the surfaceof the body or a needle port, the seal also provides an outward forceagainst the base, causing a portion of the base to be compressed againstan inner surface of the locking system. Additional seals help to form amore secure fitting between the base and the opening.

An alternate embodiment of a fiber producing device is depicted in FIGS.15A and 15B. Fiber producing device 800 includes a hub 810 and a body820. Body 820 acts as a reservoir in which material may be placed. Body820 includes one or more openings 822 through which material may exit.One or more needles 824, or other outlet elements, may be coupled toopenings 822. A hub 810 may be used to secure body 820. In anembodiment, hub 810 is a spherical hub that includes a cylindricalopening 812 to receive the body. A coupling member 830 is coupled to hub810. Coupling member 830 may be used to couple hub 810 to a driver thatis capable of rotating the hub. Coupling member 830 may be an elongatedmember extending from the body which may be coupled to a portion of thedriver (e.g., a chuck or a universal threaded joint of the driver).Alternatively, coupling member 830 may be a receiver, as depicted inFIG. 15A, which will accept an elongated member from a driver (e.g., thecoupling member may be a chuck or a universal threaded joint).

Body 820 is coupled to hub 810 by inserting the body into cylindricalcavity 812. A locking mechanism 840 is disposed in cylindrical cavity812 of hub 810. In one embodiment, locking mechanism 840 includes aspring-loaded ball 842 which rests in a cavity 844 formed in the bodyand coupled to cylindrical cavity 812. Body 820 includes an indentation826 that has a shape complementary to ball 842. To lock body 820 insidehub 810, body 820 is slid into cylindrical cavity 812. When body 820reaches locking mechanism 840, the surface of the body contacts ball 842and forces the ball into cavity 844, allowing the body to continue intothe cylindrical cavity. Body 820 is pushed through cylindrical cavityuntil indentation 826 of the body aligns with ball 842. At this point,the spring forces ball 842 into the indentation, inhibiting furthermovement of the body along cylindrical cavity 844. To ensure that body820 remains locked in hub 810, a set screw 850 may contact the body. Thepressure of set screw 850 and the resistance force of ball 842 helps toinhibit further movement of body 820 within cylindrical cavity 812. Insome embodiments, a second indentation 828 is formed in the body toreceive the set screw 850. In some embodiments, body 820 has beenpreloaded with the material to be spun. While cavity 812 and body 820are depicted as cylindrical, it should be understood that other shapesmay be used.

During use, rotation of hub 810 causes material to be ejected throughone or more of openings 822 to produce fibers. During rotation ball 842and, optionally, set screw 850 secure body 820 within hub 810. Whenfiber formation is finished, set screw 850 may be withdrawn such thatthe set screw no longer contacts body 820. Removal of the set screw 850may allow a force to be applied to body 820 sufficient to overcome theresistance created between ball 842 and body, allowing the body be slidout of hub 810. The removed body may be replaced by a second body andfiber production continued while the first body is being cleaned andreplenished with material.

FIG. 16 depicts an alternate embodiment of a fiber producing device.Fiber producing device 900 includes a spherical body 910 which definesan internal cavity. Openings are formed in a sidewall of body 910,extending through the sidewall such that the opening allows transfer ofmaterial from the internal cavity through the sidewall. The openings, inone embodiment, communicate with a coupling member 930, which iscouplable to an outlet element. In an embodiment, an outlet element 920such as a nozzle, needle port, needle, or outlet conduit, may beremovably coupled to body 910. Coupling member 960 may be used to couplebody 910 to a driver that is capable of rotating the body. Couplingmember 960 may be an elongated member extending from body 910 to aportion of a driver (e.g., a chuck or a universal threaded joint of thedriver). Alternatively, coupling member 960 may be a receiver, asdepicted in FIG. 16, which will accept an elongated member from a driver(e.g., the coupling member may be a chuck or a universal threadedjoint). Spherical body also includes an inlet port 940 that may be usedto introduce material into the internal cavity.

In some embodiments it is desirable to have a rotationally balancedsystem. Thus nozzles, needles, or needle ports are typically positionedas opposing pairs to maintain a rotationally balanced hub.Alternatively, if an odd number of nozzles, needles or needle ports areused, these devices may be positioned in a balanced orientation (e.g.,three devices can be positioned at a 120 angle from each other). In someembodiments, however, it may not be desirable to have two or moredevices that are producing fibers. It may be desirable to have only asingle fiber producing outlet from the body. While this may be achievedby simply coupling a single outlet device to the hub, such a situationmay create a rotationally unbalanced system that creates rotationalstress on the body and the driver. To offset the weight of an unpairedoutlet element, a counter weight may be coupled to an opposing (or apositionally balanced) outlet. For example, as depicted in FIG. 16, acounterweight 950 may be coupled to an opening, while an outlet element920 is coupled to the opposing opening. Thus, material only exits theoutlet element 920, while counterweight 950 inhibits material from beingejected through the opposing opening. Counterweight 950 helps to balancethe system and reduce the rotational stress on the body and driver.

In some embodiments, it may be desirable to spin two or more differentmaterials at the same time. For example, it may be desirable to spin twodifferent types of polymers, or a polymer and a metal substantiallysimultaneously. This may be used to create blended microfibers and/ornanofibers by simultaneously producing different types of fibers from asingle device. An example of a multiple level fiber producing device isdepicted in FIGS. 17A and 17B. Fiber producing device 1000 includes abody 1010 having two or more chambers. For example, in the embodimentdepicted in FIG. 17A, a fiber producing device 1000 includes threechambers, 1012, 1014, and 1016. Each of the chambers includes one ormore openings (1022, 1024, and 1026, respectively) that allow materialto be placed into the chambers. Each chamber further includes one ormore openings (1011, 1013, and 1015, respectively) through whichmaterial disposed in the chambers may be ejected. During use, rotationof the fiber producing device causes material to be ejected through oneor more of openings 1011, 1013, and 1015 of each chamber that includesmaterial to produce fibers. In some embodiments, openings 1011, 1013,and 1015 may have a size and/or shape that causes the creation ofmicrofibers and/or nanofibers as material is ejecting through theopenings. In other embodiments, outlet elements may be coupled to one ormore of openings 1011, 1013, and 1015. If different materials are placedin different chambers, two or more different fibers may thus besimultaneously produced.

In one embodiment, the chambers may be removably coupled to each other.For example, as depicted in FIGS. 17A and 17B, a second chamber 1014,may be coupled to first chamber 1012 through a coupling mechanism. In anembodiment, first chamber 1012 includes a coupling section 1032 havingthreading on the interior portion of the coupling section. Secondchamber 1014 may have complementary threading on an exterior surface ofa coupling section 1034. To assemble the multi chamber device, secondchamber 1014 may be threaded onto the first chamber 1012. In a likemanner, third chamber 1016 may be coupled to second chamber 1014.Furthermore, first chamber may be coupled to body 1010 using a similarcoupling mechanism. While three chambers are depicted, it should beunderstood that more or less than three chambers may be coupledtogether. Each chamber material inlet (1022, 1024, and 1026) may bepositioned such that material may be selectively added to each chamber(1012, 1014, and 1016, respectively), without adding material to otherchambers. A seal 1040 (e.g., an o-ring) may be placed between couplingportions of the chambers to provide a seal.

Multilevel fiber producing device 1000 includes a coupling member 1050which couples fiber producing device 1000 to a driver 1055 that iscapable of rotating the fiber producing device. Coupling member 1050 maybe an elongated member extending from the body which may be coupled to aportion of the driver (e.g., a chuck or a universal threaded joint ofthe driver). Alternatively, coupling member may be a receiver, asdepicted in FIG. 17A, which will accept an elongated member from adriver (e.g., the coupling member may be a chuck or a universal threadedjoint).

In some embodiments, it may be desirable to control the spacing betweenthe chambers. For example, as depicted in FIG. 17A, the chambers arespaced apart from each other based on the size of the coupling portions.However, the coupling portions may not create a sufficient spacing toprovide the desired separation of the chambers. In some embodiments, aspacer 1060, may be used to create additional separation between thechambers, as depicted in FIG. 17B. Use of spacers may help reduce thenumber of chambers needed to customize the fiber producing device. Forexample, rather than creating chambers having different size couplingportions, a variety of different spacers may be used to create differentspacings between the chambers without having to modify the chambers.

Another example of a multiple level fiber producing device is depictedin FIG. 17C. Fiber producing device 1000 includes a body 1010 having twoor more levels. For example, in the embodiment depicted in FIG. 17C, afiber producing device 1000 includes three levels having one or moreopenings (1011, 1013, and 1015, respectively) through which materialdisposed in the chambers may be ejected. An interior cavity 1012 of body1010 may have a curved interior surface, curving from the bottom of thecavity toward openings 1011 of the first level. In this manner, materialdisposed in cavity 1012 is directed toward openings. Generally thediameter of openings 1011, 1013, and 1015 are set such that materialmoves up the interior surface of cavity 1012 until and reaches all ofthe openings at once. The openings may be a horizontally and/orvertically displaced from each other in a predetermined pattern. Forexample, the openings may be positioned in an ordered manner to form oneor more levels of openings, as depicted in FIG. 17C.

During use, rotation of the fiber producing device causes material to beejected through one or more of openings 1011, 1013, and 1015 of eachlevel to produce fibers. In some embodiments, openings 1011, 1013, and1015 may have a size and/or shape that causes the creation ofmicrofibers and/or nanofibers as material is ejecting through theopenings. In other embodiments, outlet elements may be coupled to one ormore of openings 1011, 1013, and 1015. If different materials are placedin different chambers, two or more different fibers may thus besimultaneously produced.

In one embodiment, the levels may be removably coupled to each other.For example, as depicted in FIGS. 17C, a second level may be coupled tofirst level through a coupling mechanism. In an embodiment, couplingsection 1032 having threading on the interior portion of the couplingsection joins the first level to the second level. Second level may havecomplementary threading on an exterior surface of a coupling section1034. To assemble the multi chamber device, second level may be threadedonto the first level. In a like manner, third level may be coupled tosecond level. Furthermore, first level may be coupled to body 1010 usinga similar coupling mechanism. While three levels are depicted, it shouldbe understood that more or less than three levels may be coupledtogether. A seal 1040 (e.g., an o-ring) may be placed between couplingportions of the chambers to provide a seal.

Multilevel fiber producing device 1000 includes a coupling member 1050which couples fiber producing device 1000 to a driver 1055 that iscapable of rotating the fiber producing device. Coupling member 1050 maybe an elongated member extending from the body which may be coupled to aportion of the driver (e.g., a chuck or a universal threaded joint ofthe driver). Alternatively, coupling member may be a receiver, asdepicted in FIG. 17C, which will accept an elongated member from adriver (e.g., the coupling member may be a chuck or a universal threadedjoint).

In some embodiments, it may be desirable to control the spacing betweenthe chambers. For example, as depicted in FIG. 17C, the levels arespaced apart from each other based on the size of the coupling portions.However, the coupling portions may not create a sufficient spacing toprovide the desired separation of the levels. In some embodiments, aspacer 1060, may be used to create additional separation between thelevels, as depicted in FIG. 17B. Use of spacers may help reduce thenumber of chambers needed to customize the fiber producing device.

In some embodiments, the fiber producing device of FIG. 17C may be topmounted, as shown in FIG. 17D. Fiber producing device 1000 may becoupled to an upper support 1060 using coupling member 1030. Couplingmember 1030 may be used to couple fiber producing device 1000 to acoupling element 1042 of a driver 1040 (e.g., a chuck coupler or auniversal threaded joint of the driver). Alternatively, coupling membermay be a receiver which will accept an elongated member from a driver(e.g., the coupling member may be a chuck or a universal threadedjoint). Coupling element 1042 of driver may interact with couplingmember 1030 of the fiber producing device to allow the coupling memberto be adjustably positionable in the coupling element such that thedistance between the fiber producing device and the driver is alterable.This may be useful for applications where the produced fibers aredelivered to a substrate positioned below the fiber producing device.Assuming the substrate and driver are at a fixed distance from eachother, altering the vertical distance between the fiber producing deviceand the driver also alters the vertical distance between an underlyingsubstrate and the fiber producing device. Being able to alter thedistance between the underlying substrate and the fiber producing deviceallows the fiber deposition patterns to be altered and customized fordifferent substrates.

Another example of a multiple chamber fiber producing system is depictedin FIG. 18. Fiber producing device 1000 includes a body having two ormore chambers, as described with respect to FIGS. 17A and 17B. Each ofthe chambers includes one or more openings that allow material to beplaced into the chambers. Each chamber further includes one or moreopenings through which material disposed in the chambers may be ejected.During use, rotation of the fiber producing device causes material to beejected through one or more of the openings of each chamber thatincludes material to produce fibers. In some embodiments, openings mayhave a size and/or shape that cause the creation of microfibers and/ornanofibers by ejecting of the material through the openings. In someembodiments, one or more outlet elements may be coupled to one or moreopenings. If different materials are placed in different chambers, twoor more different fibers may be simultaneously produced.

Fiber producing device 1000 may be incorporated into a fiber producingsystem that includes at least one material feed assembly 1070 and,optionally, a heating device 1080. During use, material may be fedthrough material feed assembly 1070 into the chambers. The use of amaterial feed assembly may allow substantially continuous use of amulti-level fiber producing device. While material feed assembly 1070 isdepicted as a single tube feeder that feeds the same material to eachchamber, it should be understood that the material feed assembly may bemodified to include multiple tubes, each tube leading to a separatechamber, to allow simultaneous addition of different materials to eachchamber. Heating device 1080 may be positioned proximate to the chambersto provide heat to each of the chambers. The system may also provide anupper support 1090 for the drive shaft 1095, to help minimize vibrationand provide balancing of the system.

An alternate embodiment of a fiber producing system is depicted in FIG.19. In this embodiment, a fiber producing device 1100 includes a supportmember 1110 that includes two or more support elements 1120 coupled tothe support member. At least one of the support elements 1120 is capableof holding a body 1130 containing a material to be spun into microfibersand/or nanofibers. Support member also includes a central couplingmember 1140 that is couplable to a driver. Coupling member 1140 may bean elongated member extending from the body which may be coupled to aportion of the driver (e.g., a chuck or a universal threaded joint ofthe driver), as depicted in FIG. 19. Alternatively, coupling member maybe a receiver which will accept an elongated member from a driver (e.g.,the coupling member may be a chuck or a universal threaded joint).

In one embodiment, the fiber producing system of FIG. 19 includes one ormore support elements 1020 that hold a cylindrical body 1030 having anoutlet element 1050. Outlet element 1050 may be a nozzle, needle, needleport, or an outlet conduit. During use, one or more cylindrical bodies1030 containing a material to be spun are coupled to support elements1020. For example, cylindrical body 1030 may be inserted into acomplementary cylindrical support element 1020 having an opening toallow the outlet element to extend from the support element.Alternatively, support element may be a ring coupled to support member1110 that couples with an end portion of body 1030. Support element 1020is pivotable to allow the position of a body coupled to support elementto pivot during rotation. Rotation of support member 1110 causesmaterial to be ejected from one or more of bodies 1030 to producemicrofibers and or nanofibers. In some embodiments, less than all of thesupport elements may receive a body. In such circumstances acounterweight (e.g., a body that has a weight substantially equal to afilled body) may be placed in an opposing support element to maintainbalance for the system. Generally, the fiber producing device of FIG. 19is very similar to a tube centrifuge in operation.

Fibers created using the fiber producing devices described herein may becollected using a variety of fiber collection devices. Various exemplaryfiber collection devices are discussed below, and each of these devicesmay be combined with one another. The simplest method of fibercollection is to collect the fibers on the interior of a collection wallthat surrounds a fiber producing device. Fibers are typically collectedfrom collection walls as nonwoven fibers.

The aerodynamic flow within the chamber influences the design of thefiber collection device (e.g., height of a collection wall or rod;location of same). The spinning fiber producing device develops anaerodynamic flow within the confinement of the apparatuses describedherein. This flow may be influenced by, for example, the speed, size andshape of the fiber producing device as well as the location, shape, andsize of the fiber collection device. An intermediate wall placed outsidethe collection wall may also influence aerodynamic flow. Theintermediate wall may influence the aerodynamic flow by, for example,affecting the turbulence of the flow. Placement of an intermediate wallmay be necessary in order to cause the fibers to collect on the fibercollection device. In certain embodiments, placement of an intermediatewall can be determined through experimentation. In an embodiment, afiber producing device is operated in the presence of a fiber collectiondevice and an intermediate wall, observing whether or not fibers arecollected on the fiber collection device. If fibers are not adequatelycollected on the fiber collection device, the position of theintermediate wall is moved (e.g., making its diameter smaller or larger,or making the intermediate wall taller or shorter) and the experiment isperformed again to see if adequate collection of fibers is achieved.Repetition of this process may occur until fibers are adequatelycollected on the fiber collection device.

Typically, fibers are collected on a collection wall or settle ontoother designed structure(s). Temperature also plays a role on the sizeand morphology of the formed fibers. If the collection wall, forexample, is relatively hotter than the ambient temperature, fiberscollected on the collection wall may coalesce, leading to bundling ofand/or welding of individual fibers. In some embodiments, thetemperature of the collection wall and/or intermediate wall may becontrolled, such as, for example, by blowing gas (e.g., air, nitrogen,argon, helium) between the intermediate wall and the collection wall. Bycontrolling the flow rate, type, and temperature of this blowing gas, itis possible to control the temperature and morphology of the fibers.Wall parameters (e.g., height, location, etc.) may also influence themorphology of the fibers.

The intermediate wall may also be used to control, adjust, and/orinfluence the aerodynamic flow within the apparatus. Aerodynamic flowtypically guides the fibers to rest on one or more fiber collectiondevices. If, upon formation, loose fibers float in an apparatus (due totheir very small mass) without coming to rest on one or more fibercollection devices, it is likely that, for example, the intermediatewall is not positioned correctly, or the fiber collection device(s) isnot correctly positioned, and/or the aerodynamic flow is not properlyunderstood. An intermediate wall is typically taller than any collectionwall that may be used (e.g., about 1.1 to about 3 times as high as thecollection wall). The intermediate wall may surround a collection wallat a distance of from about 1 inch to about 5 inches, or from about 2inches to about 4 inches, or about 3 inches. Intermediate wall may beabout 10% to about 30% larger (e.g., 20% larger) than the collectionwall. An intermediate wall may be segmented, and may have one or moreholes in it.

FIG. 20A shows a top view of a fiber producing system that includes afiber producing device and a collection wall. FIG. 20B shows aprojection view of a fiber producing system that includes a fiberproducing device and a collection wall. As depicted, fiber producingdevice 1200 is spinning clockwise about a spin axis, and material isexiting openings 1206 of the body as fibers 1220 along various pathways1210. The fibers are being collected on the interior of the surroundingcollection wall 1240.

FIG. 21A depicts a perspective view of a fiber producing system 1300that includes a collection system 1310 having a plurality of collectionelements 1312 a. Fiber producing system 1300 includes a fiber producingdevice 1320 that includes a body and one or more outlet elements coupledto the body, as has been previously described. The body of fiberproducing device 1320 is coupled to a driver (not shown) that is capableof rotating the body. At least partially surrounding fiber producingdevice 1320 is a collection system 1310. In an embodiment, collectionsystem 1310 collects fibers produced during rotation of fiber producingdevice 1320. Collection system 1310 includes one or more collectionelements 1312 a coupled to a collection system substrate 1314. In anembodiment, one or more of collection elements 1312 a are in the form ofa projection extending from the collection system substrate 1314.Collection elements may be in the form of straight projections 1312 aextending from the collection system substrate 1314. In an embodiment,one or more collection elements comprise a projection comprising asubstantially flat longitudinal surface 1313 extending from thecollection element substrate to a distal end of the collection element.Use of collection elements having a flat surface assist in stopping theproduced fibers without breaking the fibers, allowing longer fibers tobe collected. One or more coatings (e.g., a teflon coating)” may beapplied to the collection elements to reduce sticking of the fibers tothe collection elements.

In an alternate embodiment, a collection element 1312 b is in the formof an arcuate projection, for example, as depicted in FIG. 21B. Use ofarcuate projections provides a surface for the produced fibers tocollect. Having an inward curved portion (curved toward the fiberproducing device) at the top of the projections helps to retain thefibers on the projections.

In an embodiment, fiber producing system 1300 also includes a collectioncontainer 1330. Collection system 1310 and fiber producing device 1320are positioned in collection container 1330. Collection container 1330allows the system to be enclosed to inhibit the loss of fibers duringproduction. A collection container lid (not shown) may be disposed onthe collection container to create a fully enclosed system.

Collection elements 1312 a may be removably coupled to collection systemsubstrate 1314 through one or more openings 1315 formed in thecollection element substrate. For example, as shown in FIG. 21, aplurality of openings may be formed in the collection element substrate1314. Collection elements 1312 a may be coupled to the collection systemsubstrate 1314 via openings 1315. For example, a collection element 1312a may include a coupling portion that is insertable into the openings1315 formed in the collection element substrate 1314. The couplingportion of collection element 1312 may be threaded and attachable bymating with a threaded opening formed in collection element substrate1314. Alternatively, openings 1315 may extend through the substrate suchthat a coupling portion of collection element 1312 a may extend throughcollection element substrate 1314. Collection element 1312 a may besecured by a coupling member attached to the coupling portion on theunderside of the substrate. Removably coupling collection elementsallows the configuration and position (e.g., the distance from the fiberproducing device) of the collection elements to be altered.

In an alternate embodiment, collection elements may be coupled to acollection substrate that allows the collection elements to berepositioned without having to remove the collection elements from thesubstrate. In one embodiment, a plurality of grooves is formed in thecollection system substrate. Collection elements are coupled to thegrooves and are movable along the grooves. In one embodiment, collectionelements may be loosened from the substrate without removing thecollection elements from the substrate. For example, loosening a nutconnecting a bolt from the collection element to the substrate may allowthe collection element to be moved along the groove. Once positioned,the nut may be retightened to secure the collection element in place.

An alternate embodiment of a collection system is depicted in FIGS. 22Aand 22B. Collection system 1400 includes a collection substrate 1410that includes at least a first disk 1412 and a second disk 1414. Firstdisk 1412 includes a plurality of grooves 1413 and second disk 1414includes a plurality of grooves 1415. First disk 1412 is coupled tosecond disk 1414 such that portions of the grooves of the first andsecond disks are aligned, as depicted in FIG. 22A. Grooves 1413 of firstdisk 1412 are formed extending radially in a direction from the centerof the first disk. Grooves 1415 of second disk 1414 are formed suchthat, when the centers of the first disk and second disk are coupledtogether, grooves 1415 of the second disk are at an angle with respectto grooves 1413 of the first disk. In some embodiments, grooves 1415 onsecond disk 1413 form an angle of about 45 with respect to grooves 1413on first disk 1412, when the first disk and the second disk are coupledtogether. Collection elements 1420 are coupled to first disk 1412 andsecond disk 1414. In one embodiment, a coupling portion 1422 ofcollection element 1420 extends through one of grooves 1413 in firstdisk 1412 and one of grooves 1415 of second disk 1414, as depicted inFIG. 22B. Coupling portion 1422 may include a fastener 1423 coupled tothe coupling portion to help inhibit removal of collection element 1420from collection substrate 1410. With collection elements 1420 coupled tofirst disk 1412 and second disk 1414, the position of the collectionelements may be altered by rotating the first disk with respect to thesecond disk. For example, in the embodiment depicted in FIG. 22A, asfirst disk 1412 is rotated in a clockwise direction, collection elements1420 are forced along groove 1413 of the first disk and groove 1415 ofsecond disk 1414 to a position further away from the center of thedisks. In this manner, the effective diameter of the collection system(i.e., the distance the collection elements are from the center of thecollection substrate) may be increased by clockwise of first disk 1412.To decrease the effective diameter of the collection system, first disk1412 may be rotated in a counter-clockwise direction, causing collectionelements 1420 to move toward the center of the first and second disks.

An alternate collection system is depicted in FIGS. 23A-23C. In anembodiment, a fiber producing device and a collection system are placedin a collection container. The collection system includes one or morecollection elements coupled to a collection substrate. The collectionsubstrate may be removably positionable within the collection containerto adjust the position of the collection elements. In one embodiment,the collection elements are arcuate projections extending from thecollection substrate, as previously described. FIG. 23A depicts anembodiment of a collection container 1500 capable of receiving acollection substrate. For example, a collection container 1500 mayinclude one or more indentations 1510, configured to mate with one ormore collection tabs formed on a collection substrate. FIG. 23B depictsa collection substrate 1520 having collection tabs 1525 that may be usedto couple the collection substrate to collection container 1500. Forexample, tabs 1525 of collection substrate may be matched withindentations 1510 of collection container 1500 to allow the collectionsubstrate to be removably positioned in the collection contained. FIG.23C depicts collection substrate 1520 placed in a collection container1500.

When desired, collection substrate 1520 may be removed from collectioncontainer 1500 and an alternate collection substrate may be placed inthe collection container. For example, a collection substrate thatincludes collection elements that are closer or farther from the centerof the collection container. In other embodiments, the collectionsubstrate may be removed from the collection container and replaced witha collection substrate having collection elements positioned indifferent positions than the removed collection substrate. In thismanner, the orientation of the collection elements may be modifiedwithout having to individually remove collection elements.

For many applications, it may be desirable to substantially continuouslyproduce nanofibers and/or microfibers. For fiber producing systems thatmake use of fiber collection elements, the removal of fiber from thecollection system typically requires a stoppage of fiber production toallow removal of fibers from the collection elements. In an alternateembodiment a diversion device may be used to allow fiber production tocontinue while the produced fibers are being collected. FIG. 24 depictsan embodiment of a fiber producing system 1600 that includes a fiberproducing device 1610 and a diversion device 1620 positionable betweenthe fiber producing device and collection elements 1630. As fibers areproduced by the fiber producing device 1610, the fibers may be collectedon collection elements 1630 that are disposed around the fiber producingdevice. As the amount of fiber collected on collection elements 1630increases, the collection elements may reach a point that the fibers areno longer being collected on the collection element and instead arebeing deposited inside the interior of the system. At this point thefibers may need to be removed from the collection element before furthercollection of the fibers may be accomplished. In an embodiment, adiversion device 1620 may be positioned between fiber producing device1610 and the collection elements 1630 to divert the fibers beingproduced by the fiber producing device into a collection container 1640.While the fibers are diverted, material from collection elements 1630may be removed and collected. Once collection elements 1630 aresufficiently cleared, diversion device 1620 may be removed andcollection of the fibers on collection elements 1630 may be continued.In this way fiber collection may be accomplished without stopping thefiber producing device. The diverted fibers collected in the collectioncontainer may be used to form products, or recycled by combining withunspun material to form a material feed for the fiber producing device.In this manner, waste of material may be minimized.

Diversion may also be used at startup of the fiber producing system. Forexample, when rotation of the fiber producing device is initiated, thefibers being produced may not meet the desired specifications regardingsize and/or consistency. The diversion device may be positioned betweenthe fiber producing device and the collection elements in order todivert the produced fibers until the desired quality requirements aremet, typically after a predetermined time. Once the desired fibers arebeing produced the diversion system may be removed to allow the fibersto be collected on the collection elements. The diverted material may bedisposed of, reintroduced into the fiber producing device, or blendedwith unused material to form a material feed for the fiber producingdevice.

The conditions of the environment in which fibers are created mayinfluence various properties of those fibers. For example, some metallicfibers, such as iron fibers, react with ambient air (becoming convertedto iron oxides). For such applications, it is preferable to replaceambient air with an inert gas (e.g., nitrogen, helium, argon). Humidconditions may detrimentally affect the surfaces of many polymericfibers, such as poly(ethylene oxide) (PEO) fibers. Thus, loweringhumidity levels is preferable for processing of some materials.Similarly, drugs may be required to be developed under sterileconditions that are not maintained in ambient conditions, a sterileenvironment is therefore preferred in such situations.

The “environment” refers to the interior space defined by the housingthat surrounds the components of a fiber producing device. For certainuses, the environment may simply be ambient air. Air may be blown intothe environment, if desired. For other uses, the environment may besubjected to low-pressure conditions, such as from about 1 mm Hg toabout 760 mm Hg, or any range derivable therein using, for example, avacuum pump. Alternatively, the environment may be subjected tohigh-pressure conditions, such as conditions ranging from 761 mm Hg upto 4 atm or higher using, for example, a high pressure pump. Thetemperature of the environment may be lowered or raised, as desired,through the use of heating and/or cooling systems, which are describedbelow. The humidity level of the environment may be altered using ahumidifier, and may range from 0% to 100% humidity. For certainapplications, such as drug development, the environment may be renderedsterile. If the components of an apparatus are each made of, forexample, stainless steel, all components may be individually sterilizedand assembled, such as in a clean room under conditions that maintainthe sterility of the apparatus.

Several types of heating and cooling sources may be used in apparatusesand methods as discussed herein to independently control the temperatureof, for example, a fiber producing device, a collection wall, anintermediate wall, a material, and/or the environment within anapparatus. Examples of heat sources that may be employed includeresistance heaters, inductive heaters and radiant heaters (e.g. infraredheaters). Peltier or Thermoelectric Cooling (TEC) devices may be usedfor heating and/or cooling purposes. Cold gas or heated gas (e.g., airor nitrogen) may also be pumped into the environment for cooling orheating purposes. Conductive, convective, or radiation heat transfermechanisms may be used for heating and cooling of various components ofthe apparatuses.

FIG. 25 shows a perspective view of an embodiment of a fiber producingsystem 1700. System 1700 includes a fiber producing device disposed in acollection container 1710 as has been previously described. Collectioncontainer 1710 is positioned in housing 1720, which creates an enclosedenvironment for fiber production. Driver 1730, such as a variable speedmotor, is coupled to a fiber producing device disposed in collectioncontainer 1710. A heating unit (not shown) is enclosed within housing1720 and directs heat (thermal energy) to the fiber producing deviceand/or the environment. While a single fiber producing system isdepicted in the housing, it should be understood that multiple fiberproducing systems may be disposed in the same housing. In someembodiments, multiple fiber producing systems may be coupled to multipledrivers and disposed in a housing. In some embodiments, multiple fiberproducing systems may be coupled to a single driver, for example, on asingle driver axel that is coupled to the multiple fiber producingdevices.

An inlet port 1740 is coupled to housing 1720, extending into theinterior of the housing. Inlet port 1740 may be used to input gasses(e.g., gases such as air, nitrogen, helium, argon, etc.) into theinternal environment of housing 1720, or allows gasses to be pumped outof the internal environment of the housing 1720. Inlet port 1740 mayalso include one or more conduits for conveying material to the fiberproducing device. For example, a fiber producing device may include anopening in the top surface of the device, as has been shown previously.Alignment and/or coupling of an inlet tube with the opening may allowmaterial to be sent to the fiber producing device when the device isbeing prepared to be used, or while the device is spinning (to allowcontinuous production of fibers) while the housing is closed.

Indicators for power and electronics and control switches 1750 arepositioned on the exterior of a wall of housing 1720. A control systemof the fiber producing system may allow a user to change certainparameters (e.g., RPM, temperature, and environment) to influence fiberproperties. One parameter may be changed while other parameters are heldconstant, if desired. One or more control boxes in an apparatus mayprovide various controls for these parameters, or certain parameters maybe controlled via other means (e.g., manual opening of a valve attachedto a housing to allow a gas to pass through the housing and into theenvironment of an apparatus). It should be noted that the control systemmay be integral to the apparatus (as shown in FIG. 25) or may beseparate from the housing. For example, a control system may be modularwith suitable electrical connections to the fiber producing system.

Components of apparatuses may be made from a variety of materials. Incertain embodiments, the components of an apparatus may be made fromstainless steel. For example, the fiber producing device, collectionwall and housing may each be made from stainless steel.

In this situation, the components may be used for, e.g., low meltingmetals like tin (232° C.), zinc (420° C.), silver (962° C.) and alloysthereof. In certain embodiments, ceramic components may be used for highmelting alloys, such as gold (1064° C.) and nickel (1453° C.).Manipulation of high melting alloys may require blanketing theenvironment of the components with an inert gas, such as nitrogen orhelium, with appropriate sealing of the housing.

In certain methods described herein, material spun in a fiber producingdevice may undergo varying strain rates, where the material is kept as amelt or solution. Since the strain rate alters the mechanical stretchingof the fibers created, final fiber dimension and morphology may besignificantly altered by the strain rate applied. Strain rates areaffected by, for example, the shape, size, type and RPM of a fiberproducing device. Altering the viscosity of the material, such as byincreasing or decreasing its temperature or adding additives (e.g.,thinner), may also impact strain rate. Strain rates may be controlled bya variable speed fiber producing device. Strain rates applied to amaterial may be varied by, for example, as much as 50-fold (e.g., 1000rpm to 25,000 RPM).

Temperatures of the material, fiber producing device and the environmentmay be independently controlled using a control system. The temperaturevalue or range of temperatures employed typically depends on theintended application. For example, for many applications, temperaturesof the material, fiber producing device and the environment typicallyrange from −4° C. to 400° C. Temperatures may range as low as, forexample, −20° C. to as high as, for example, 2500 C. For melt spinningof polymers, a fiber producing device may be kept at a temperature of upto 200° C. For melt spinning involving metals, a fiber producing devicemay be kept at temperatures of 450° C. or higher. For solution spinning,ambient temperatures of the fiber producing device are typically used.In drug development studies the temperature of the fiber producingdevice may be between, for example, 4° C. and 80° C. When producingceramic or metal fibers, the temperatures utilized may be significantlyhigher. For higher temperatures, it will typically be necessary to makeappropriate changes in the materials of the housing of an apparatusand/or the interior components (e.g., substitution of metal forplastic), or in the apparatus itself (e.g., addition of insulation).Such changes may also help avoid undesirable reactions, such asoxidation.

The level of material in the fiber producing device may be monitored bya control system. In an embodiment, inlet port 1730 may include one ormore fluid sensors that are positioned proximate to the fiber producingdevice, in a position that allows the fluid sensor to measure the levelof fluid in the fiber producing device. In one embodiment, a fluidsensor is an optical fluid level sensor that is optically coupled to thefluid in the fiber producing device. Examples of optical fluid sensorsinclude, but are not limited to, laser fluid sensors, infrared fluidsensors, and ultraviolet fluid sensors. Optical fluid sensors includeLED based fluid sensors. In other embodiments, a fluid level sensor isan ultrasonic fluid level sensor. The fluid sensor may be coupled to acontroller. During use, controller may discontinue production of fibersif the fluid level in the fiber producing device is below apredetermined level. In other embodiments, controller may send a controlsignal to a material supply source to send more material into the fiberproducing device, if the fluid level inside of the fiber producingdevice falls below a predetermined level. Inlet port 1730 may includeone or more conduits coupled to a material supply source that conveysthe material to the fiber producing device when a control signal isreceived.

Generally, it is preferred that fibers produced in a fiber producingsystem are collected without being contacted by the users. An embodimentof a fiber producing system that includes a collection system isdepicted in FIG. 26. Fiber producing system 1800 includes a fiberproducing device 1810 coupled to a driver. A collection system 1820 atleast partially surrounds fiber producing device 1810. Collection system1820 may include one or more collection elements 1825 positioned aroundfiber producing device 1810, a gas flow device 1830, a collectionconduit 1835 and a collection chamber 1840. During use fibers producedby fiber producing device 1810 are collected on collection elements1825. As the amount of fiber collected on collection elements 1825increases, the collection elements may reach a point that the fibersbegin to be deposited inside collection conduit 1835. Activation of gasflow device 1830 creates a flow of gas through the fiber producingsystem flowing toward a collection chamber 1840. In an embodiment, gasflows from collection elements 1820 toward collection chamber 1840. Theflow of gas may dislodge collected fiber from collection elements 1825and direct the dislodged fibers toward collection chamber 1840. In oneembodiment, gas flow device 1830 is activated when the fibers collectedon collection elements 1825 reach a predetermined amount. Alternatively,gas flow device 1830 may be run continuously as the fibers are produced.The collection system may further include a collection conduit 1835surrounding at least a portion of the fiber producing device. Collectionchamber 1840 is coupled to collection conduit 1835. Gas flow device 1830is coupled to collection conduit 1835. Gas produced by gas flow device1830 creates a current of gas flowing through collection conduit 1835toward collection chamber 1840. The produced fibers are transferredthrough collection conduit 1835 to collection chamber 1840 by the gasflow produced by the gas flow device. Collection conduit 1835 may be aseparate conduit formed to conduct the fiber to the chamber.Alternatively, a wall of a collection container, as described earlier,may define at least the outer wall of the collection conduit.

In another embodiment, collection elements 1825 may be cutting elements(e.g., wires) that are capable of cutting and/or breaking the fibersthat are produced by the fiber producing device. The wires may extendfrom a bottom surface of the collection substrate toward a top surfaceof the collection system. The cut or broken fibers are pulled by the gasproduced by the gas flow device, through a collection conduit, into thechamber.

An embodiment of a fiber producing system that includes a collectionsystem is depicted in FIG. 27. Fiber producing system 1800 includes afiber producing device 1810 coupled to a driver. A collection system1820 at least partially surrounds fiber producing device 1810.Collection system 1820 may include one or more collection elements 1825positioned around fiber producing device 1810, a gas flow device 1830, acollection conduit 1835 and a collection chamber 1840. During use fibersproduced by fiber producing device 1810 are collected on collectionelements 1825. As the amount of fiber collected on collection elements1825 increases, the collection elements may reach a point that thefibers begin to be deposited inside collection conduit 1835. Activationof a vacuum device 1845, positioned, e.g., in a collection chambercreates a flow of gas through the fiber producing system flowing towardthe collection chamber 1840. In an embodiment, gas flows from collectionelements 1820 toward collection chamber 1840. The flow of gas maydislodge collected fiber from collection elements 1825 and direct thedislodged fibers toward collection chamber 1840. In one embodiment, gasflow device 1830 is activated when the fibers collected on collectionelements 1825 reach a predetermined amount. Alternatively, gas flowdevice 1830 may be run continuously as the fibers are produced. Thecollection system may further include a collection conduit 1835surrounding at least a portion of the fiber producing device. Collectionchamber 1840 is coupled to collection conduit 1835. Gas flow device 1830is coupled to collection conduit 1835. A vacuum device 1845 creates acurrent of gas flowing through collection conduit 1835 toward collectionchamber 1840. The produced fibers are transferred through collectionconduit 1835 to collection chamber 1840 by the gas flow produced by thegas flow device. Collection conduit 1835 may be a separate conduitformed to conduct the fiber to the chamber. Alternatively, a wall of acollection container, as described earlier, may define at least theouter wall of the collection conduit.

In another embodiment, collection elements 1825 may be cutting elements(e.g., wires) that are capable of cutting and/or breaking the fibersthat are produced by the fiber producing device. The wires may extendfrom a bottom surface of the collection substrate toward a top surfaceof the collection system. The cut or broken fibers are pulled by the gasproduced by the gas flow device, through a collection conduit, into thechamber.

Another embodiment of a fiber producing system is depicted in FIG. 28.Fiber producing system 1900 includes a fiber producing device 1910.Fiber producing device includes a body 1912 and a coupling member 1914.Body 1912 comprises one or more openings 1916 through which materialdisposed in the body may pass through during use. One or more outletelements 1918 (e.g., nozzles, needles, needle ports or outlet conduits)may be coupled to one or more openings 1916. As discussed previously,interior cavity of the body may include angled or rounded walls to helpdirect material disposed in body 1912 toward openings 1916. Couplingmember 1914 may be an elongated member (as depicted in FIG. 28)extending from the body which may be coupled to a portion of a driver1920 (e.g., a chuck or a universal threaded joint of the driver).Alternatively, coupling member may be a receiver which will accept anelongated member from a driver (e.g., the coupling member may be a chuckor a universal threaded joint).

Fiber producing system may include a driver 1920 coupled to couplingmember 1914. Driver 1920 is positioned above fiber producing device 1910when the fiber producing device is coupled to the driver. Driver 1920 iscapable of rotating fiber producing device 1910 during use. Suitabledrivers include commercially available variable electric motors, such asa brushless DC motor.

Fiber producing system 1900 may further include a collection system1930. Collection system may include a collection wall 1932 at leastpartially surrounding fiber producing device 1910. Collection system1930 may further include a collection conduit 1934 coupled to collectionwall 1932. Collection conduit 1934, in one embodiment, may be anintegral part of collection wall 1932. During use, fibers produced byfiber producing device 1910 may collect on collection wall 1932 and betransferred to collection conduit 1934. In one embodiment, collectionconduit 1934 is positioned below fiber producing device 1910 such thatthe produced fibers are collected on collection wall 1932 and fall intothe collection conduit. In some embodiments, a gas flow device (notshown) or a vacuum system (not shown) may be used to create a gas streamconducting fibers from collection wall 1932 toward collection conduit1934. Collection conduit 1934 may be coupled to a collection chamberthat is used to collect fibers.

In an embodiment, a fiber producing system may be used to depositmicrofibers and/or nanofibers on a substrate. An embodiment of adeposition system 2000 configured for deposition of fibers on asubstrate is shown in FIG. 29. Any fiber producing device, as describedpreviously may be coupled to deposition system 2000. Deposition system2000 includes an inlet conduit 2010 and a substrate support 2020. Inletconduit 2010 may be coupled to either a fiber producing device, or acollection chamber that collects fibers from a fiber producing device.During use fibers are conducted through inlet conduit 2010 intodeposition system 2000 where the microfibers and/or nanofibers producedby the fiber producing device are deposited onto a substrate 2030. Asubstrate 2030 may be held in a fixed position by substrate support2020. Substrate support 2020 may position substrate 2030 in a flow ofmicrofibers and/or nanofibers created in deposition system 2000.

In an embodiment, a flow of fibers may be created using a gas flowsystem, a vacuum, or a combination of a gas flow system and vacuum. Forexample, in one embodiment, a gas flow generator 2040 may be disposed ina bottom of deposition system 2000. During use a flow of gas is created,flowing from the bottom of deposition system 2000 toward substrate 2030.The fibers that are generated and passed to deposition system 2000 aredirected into the substrate by the gas flow. Alternatively, a fibercollection system coupled to inlet conduit 2010 may produce a gas flow,as described above, that causes a stream of fibers to flow through theinlet conduit into deposition system 2000. A fiber deflector 2012 may becoupled to inlet conduit 2010 to direct incoming fibers toward substrate2030.

In an alternate embodiment, a vacuum device 2022 is coupled todeposition system 2000. In an embodiment, vacuum system 2022 is coupledto substrate support 2020. During use, a vacuum is applied to an upperchamber 2025 formed between substrate support 2020 and the top ofdeposition system 2000. A lower chamber 2045 is defined by substratesupport 2020 and the bottom of deposition system 2000. Lower chamber2045 includes inlet conduit 2010. Substrate support 2020 may have one ormore openings 2024 that pass through the substrate support, couplingupper chamber 2025 to lower chamber 2045. Application of a vacuum toupper chamber 2025 creates a flow of gas from lower chamber 2045thorough substrate support 2020, to upper chamber 2025. Thus fibersdisposed in lower chamber are drawn toward and into substrate 2030disposed on substrate support 2020. A vacuum created in upper chambermay also provide a holding force to hold substrate 2030 againstsubstrate support 2020.

In an embodiment, both a gas flow device and a vacuum system may be usedtogether to create a flow of fibers in deposition system 2000. Forexample, gas flow device 2040 may be disposed at the bottom ofdeposition system 2000, or may be part of the fiber producing systemcoupled to the deposition system. Gas flow device 2040 creates a flow offibers through inlet conduit 2010 into deposition system 2000 and towardsubstrate 2030. Deposition system 2000 may also include a vacuum device2022 coupled to upper chamber 2025. During use, a vacuum is applied toupper chamber 2025 creating a flow of gas from lower chamber 2045 towardthe upper chamber. Gas coming in from gas flow device 2040 or from inletconduit, helps provide a gas flow from lower chamber 2045 toward thesubstrate 2030. The fibers directed to substrate 2030, in someembodiments, may become at least partially embedded in the substrate.

In an embodiment, deposition system 2000 may be used to depositmicrofibers and/or nanofibers on a moving substrate. In an embodiment,substrate support 2020 may allow substrate 2030 to be moved throughdeposition system 2000, positioning the portion of the substrate that isdisposed in the deposition system in a flow of microfibers and/ornanofibers. In an embodiment, a substrate 2030 may be a sheet ofmaterial having a length that is longer than the length of depositionsystem 2000. The sheet of material may be passed through depositionsystem 2000 at a rate that allows a predetermined amount of fibers to bedeposited on the substrate before the substrate exits the depositionsystem. The substrate may be coupled to a substrate conveyance systemthat moves the substrate through the deposition system.

An alternate embodiment of a continuous feed substrate deposition systemis depicted in FIG. 30. In FIG. 30 deposition of microfibers and/ornanofibers is performed in the fiber producing system, rather than in aseparate deposition system. For example, in place of the collectionelements described above with respect to fiber producing systems, fiberproducing system 2100 includes a substrate support 2120 positionedaround at least a portion of a fiber producing device 2010. As depictedin FIG. 30, a substrate support 2120 may be configured for continuousfeeding of a substrate 2130 past fiber producing device 2010.Alternatively, substrate support 2020 may hold an entire substrateproximate to the fiber producing device. In the embodiment depicted inFIG. 30, substrate support 2020 is curved around at least a portion offiber producing device 2010. In some embodiments, substrate support 2020may be positioned substantially completely around fiber producing device2010. Substrate support 2020 includes a substantially rounded edge thatallows continuous feed of the substrate at an angle. During use, asubstrate may be fed through the fiber deposition system over substratesupport 2020. As the substrate is fed through the fiber producingsystem, fiber producing device 2010 may be operated to producemicrofibers and/or nanofibers that are deposited on the substrate.

In an embodiment, to control fiber length, one or more cutting elements2050 may be positioned between fiber producing device 2010 and substratesupport 2020. Cutting elements 2050 may be positioned to cut and/orbreak fibers, produced by the fiber producing device prior to the fibersreaching the substrate.

Fibers represent a class of materials that are continuous filaments orthat are in discrete elongated pieces, similar to lengths of thread.Fibers are of great importance in the biology of both plants andanimals, e.g., for holding tissues together. Human uses for fibers arediverse. For example, fibers may be spun into filaments, thread, string,or rope. Fibers may also be used as a component of composite materials.Fibers may also be matted into sheets to make products such as paper orfelt. Fibers are often used in the manufacture of other materials.

Fibers as discussed herein may be created using, for example, a solutionspinning method or a melt spinning method. In both the melt and solutionspinning methods, a material may be put into a fiber producing devicewhich is spun at various speeds until fibers of appropriate dimensionsare made. The material may be formed, for example, by melting a soluteor may be a solution formed by dissolving a mixture of a solute and asolvent. Any solution or melt familiar to those of ordinary skill in theart may be employed. For solution spinning, a material may be designedto achieve a desired viscosity, or a surfactant may be added to improveflow, or a plasticizer may be added to soften a rigid fiber. In meltspinning, solid particles may comprise, for example, a metal or apolymer, wherein polymer additives may be combined with the latter.Certain materials may be added for alloying purposes (e.g., metals) oradding value (such as antioxidant or colorant properties) to the desiredfibers.

Non-limiting examples of reagents that may be melted, or dissolved orcombined with a solvent to form a material for melt or solution spinningmethods include polyolefin, polyacetal, polyamide, polyester, celluloseether and ester, polyalkylene sulfide, polyarylene oxide, polysulfone,modified polysulfone polymers and mixtures thereof. Non-limitingexamples of solvents that may be used include oils, lipids and organicsolvents such as DMSO, toluene and alcohols. Water, such as de-ionizedwater, may also be used as a solvent. For safety purposes, non-flammablesolvents are preferred.

In either the solution or melt spinning method, as the material isejected from the spinning fiber producing device, thin jets of thematerial are simultaneously stretched and dried or stretched and cooledin the surrounding environment. Interactions between the material andthe environment at a high strain rate (due to stretching) leads tosolidification of the material into fibers, which may be accompanied byevaporation of solvent. By manipulating the temperature and strain rate,the viscosity of the material may be controlled to manipulate the sizeand morphology of the fibers that are created. A wide variety of fibersmay be created using the present methods, including novel fibers such aspolypropylene (PP) nanofibers. Non-limiting examples of fibers madeusing the melt spinning method include polypropylene, acrylonitrilebutadiene styrene (ABS) and nylon. Non-limiting examples of fibers madeusing the solution spinning method include polyethylene oxide (PEO) andbeta-lactams.

The creation of fibers may be done in batch modes or in continuousmodes. In the latter case, material can fed continuously into the fiberproducing device and the process can be continued over days (e.g., 1-7days) and even weeks (e.g., 1-4 weeks).

The methods discussed herein may be used to create, for example,nanocomposites and functionally graded materials that can be used forfields as diverse as, for example, drug delivery and ultrafiltration(such as electrets). Metallic and ceramic nanofibers, for example, maybe manufactured by controlling various parameters, such as materialselection and temperature. At a minimum, the methods and apparatusesdiscussed herein may find application in any industry that utilizesmicro- to nano-sized fibers and/or micro- to nano-sized composites. Suchindustries include, but are not limited to, material engineering,mechanical engineering, military/defense industries, biotechnology,medical devices, tissue engineering industries, food engineering, drugdelivery, electrical industries, or in ultrafiltration and/ormicro-electric mechanical systems (MEMS).

Some embodiments of a fiber producing device may be used for melt and/orsolution processes. Some embodiments of a fiber producing device may beused for making organic and/or inorganic fibers. With appropriatemanipulation of the environment and process, it is possible to formfibers of various configurations, such as continuous, discontinuous,mat, random fibers, unidirectional fibers, woven and nonwoven, as wellas fiber shapes, such as circular, elliptical and rectangular (e.g.,ribbon). Other shapes are also possible. The produced fibers may besingle lumen or multi-lumen.

By controlling the process parameters, fibers can be made in micron,sub-micron and nano-sizes, and combinations thereof. In general, thefibers created will have a relatively narrow distribution of fiberdiameters. Some variation in diameter and cross-sectional configurationmay occur along the length of individual fibers and between fibers.

Generally speaking, a fiber producing device helps control variousproperties of the fibers, such as the cross-sectional shape and diametersize of the fibers. More particularly, the speed and temperature of afiber producing device, as well as the cross-sectional shape, diametersize and angle of the outlets in a fiber producing device, all may helpcontrol the cross-sectional shape and diameter size of the fibers.Lengths of fibers produced may also be influenced by the choice of fiberproducing device used.

The temperature of the fiber producing device may influence fiberproperties, in certain embodiments. Both resistance and inductanceheaters may be used as heat sources to heat a fiber producing device. Incertain embodiments, the fiber producing device is thermally coupled toa heat source that may be used to adjust the temperature of the fiberproducing device before spinning, during spinning, or both beforespinning and during spinning. In some embodiments, the fiber producingdevice is cooled. For example, a fiber producing device may be thermallycoupled to a cooling source that can be used to adjust the temperatureof the fiber producing device before spinning, during spinning, orbefore and during spinning. Temperatures of a fiber producing device mayrange widely. For example, a fiber producing device may be cooled to aslow as −20 C or heated to as high as 2500 C. Temperatures below andabove these exemplary values are also possible. In certain embodiments,the temperature of a fiber producing device before and/or duringspinning is between about 4° C. and about 400° C. The temperature of afiber producing device may be measured by using, for example, aninfrared thermometer or a thermocouple.

The speed at which a fiber producing device is spun may also influencefiber properties. The speed of the fiber producing device may be fixedwhile the fiber producing device is spinning, or may be adjusted whilethe fiber producing device is spinning. Those fiber producing deviceswhose speed may be adjusted may, in certain embodiments, becharacterized as variable speed fiber producing devices. In the methodsdescribed herein, the fiber producing device may be spun at a speed ofabout 500 RPM to about 25,000 RPM, or any range derivable therein. Incertain embodiments, the fiber producing device is spun at a speed of nomore than about 50,000 RPM, about 45,000 RPM, about 40,000 RPM, about35,000 RPM, about 30,000 RPM, about 25,000 RPM, about 20,000 RPM, about15,000 RPM, about 10,000 RPM, about 5,000 RPM, or about 1,000 RPM. Incertain embodiments, the fiber producing device is rotated at a rate ofabout 5,000 RPM to about 25,000 RPM.

In an embodiment, a method of creating fibers, such as microfibersand/or nanofibers, includes: heating a material; placing the material ina heated fiber producing device; and, after placing the heated materialin the heated fiber producing device, rotating the fiber producingdevice to eject material to create nanofibers from the material. In someembodiments, the fibers may be microfibers and/or nanofibers. A heatedfiber producing device is a structure that has a temperature that isgreater than ambient temperature. “Heating a material” is defined asraising the temperature of that material to a temperature above ambienttemperature. “Melting a material” is defined herein as raising thetemperature of the material to a temperature greater than the meltingpoint of the material, or, for polymeric materials, raising thetemperature above the glass transition temperature for the polymericmaterial. In alternate embodiments, the fiber producing device is notheated. Indeed, for any embodiment that employs a fiber producing devicethat may be heated, the fiber producing device may be used withoutheating. In some embodiments, the fiber producing device is heated butthe material is not heated. The material becomes heated once placed incontact with the heated fiber producing device. In some embodiments, thematerial is heated and the fiber producing device is not heated. Thefiber producing device becomes heated once it comes into contact withthe heated material.

A wide range of volumes/amounts of material may be used to producefibers. In addition, a wide range of rotation times may also beemployed. For example, in certain embodiments, at least 5 milliliters(mL) of material are positioned in a fiber producing device, and thefiber producing device is rotated for at least about 10 seconds. Asdiscussed above, the rotation may be at a rate of about 500 RPM to about25,000 RPM, for example. The amount of material may range from mL toliters (L), or any range derivable therein. For example, in certainembodiments, at least about 50 mL to about 100 mL of the material arepositioned in the fiber producing device, and the fiber producing deviceis rotated at a rate of about 500 RPM to about 25,000 RPM for about 300seconds to about 2,000 seconds. In certain embodiments, at least about 5mL to about 100 mL of the material are positioned in the fiber producingdevice, and the fiber producing device is rotated at a rate of 500 RPMto about 25,000 RPM for 10-500 seconds. In certain embodiments, at least100 mL to about 1,000 mL of material is positioned in the fiberproducing device, and the fiber producing device is rotated at a rate of500 RPM to about 25,000 RPM for about 100 seconds to about 5,000seconds. Other combinations of amounts of material, RPMs and seconds arecontemplated as well.

Typical dimensions for fiber producing devices are in the range ofseveral inches in diameter and in height. In some embodiments, a fiberproducing device has a diameter of between about 1 inch to about 60inches, from about 2 inches to about 30 inches, or from about 5 inchesto about 25 inches. The height of the fiber producing device may rangefrom about 1 inch to about 10 inches, from about 2 inches to about 8inches, or from about 3 inches to about 5 inches.

In certain embodiments, fiber producing device includes at least oneopening and the material is extruded through the opening to create thenanofibers. In certain embodiments, the fiber producing device includesmultiple openings and the material is extruded through the multipleopenings to create the nanofibers. These openings may be of a variety ofshapes (e.g., circular, elliptical, rectangular, square) and of avariety of diameter sizes (e.g., 0.01-0.80 mm).

When multiple openings are employed, not every opening need be identicalto another opening, but in certain embodiments, every opening is of thesame configuration. Some opens may include a divider that divides thematerial, as the material passes through the openings. The dividedmaterial may form multi-lumen fibers.

In one embodiment, coaxial fibers may be produced using an outletelement having a two or more coaxial conduits. FIG. 32 depicts an outletelement 3200 having an outer conduit 3210 and an inner conduit 3220. Theinner conduit 3220 is sized and positioned inside of the outer conduit3210 such that the material may flow through the inner conduit and theouter conduit during use. The outlet element 3200 depicted in FIG. 32may be part of a needle or nozzle (e.g., a nozzle tip). The use of anoutlet element 3200 having coaxial conduits allows the formation ofcoaxial fibers. Different materials may be passed through each ofconduits 3210/3220 to produce fibers of mixed materials in which aninner fiber (produced from the inner conduit) is at least partiallysurrounded by an outer fiber (produced from the outer conduit). Theformation of coaxial fibers may allow fibers to be formed havingdifferent properties that are selectable based on the materials used toform the fibers. Alternatively, the same material passes through each ofconduits 3210/3220 forming a coaxial fiber formed from the samematerial.

In an embodiment, material may be positioned in a reservoir of a fiberproducing device. The reservoir may, for example, be defined by aconcave cavity of the heated structure. In certain embodiments, theheated structure includes one or more openings in communication with theconcave cavity. The fibers are extruded through the opening while thefiber producing device is rotated about a spin axis. The one or moreopenings have an opening axis that is not parallel with the spin axis.The fiber producing device may include a body that includes the concavecavity and a lid positioned above the body.

Another fiber producing device variable includes the material(s) used tomake the fiber producing device. Fiber producing devices may be made ofa variety of materials, including metals (e.g., brass, aluminum,stainless steel) and/or polymers. The choice of material depends on, forexample, the temperature the material is to be heated to, or whethersterile conditions are desired.

Any method described herein may further comprise collecting at leastsome of the microfibers and/or nanofibers that are created. As usedherein “collecting” of fibers refers to fibers coming to rest against afiber collection device. After the fibers are collected, the fibers maybe removed from a fiber collection device by a human or robot. A varietyof methods and fiber (e.g., nanofiber) collection devices may be used tocollect fibers.

Regarding the fibers that are collected, in certain embodiments, atleast some of the fibers that are collected are continuous,discontinuous, mat, woven, nonwoven or a mixture of theseconfigurations. In some embodiments, the fibers are not bundled into acone shape after their creation. In some embodiments, the fibers are notbundled into a cone shape during their creation. In particularembodiments, fibers are not shaped into a particular configuration, suchas a cone figuration, using gas, such as ambient air, that is blown ontothe fibers as they are created and/or after they are created.

Present method may further comprise, for example, introducing a gasthrough an inlet in a housing, where the housing surrounds at least theheated structure. The gas may be, for example, nitrogen, helium, argon,or oxygen. A mixture of gases may be employed, in certain embodiments.

The environment in which the fibers are created may comprise a varietyof conditions. For example, any fiber discussed herein may be created ina sterile environment. As used herein, the term “sterile environment”refers to an environment where greater than 99% of living germs and/ormicroorganisms have been removed. In certain embodiments, “sterileenvironment” refers to an environment substantially free of living germsand/or microorganisms. The fiber may be created, for example, in avacuum. For example the pressure inside a fiber producing system may beless than ambient pressure. In some embodiments, the pressure inside afiber producing system may range from about 1 millimeters (mm) ofmercury (Hg) to about 700 mm Hg. In other embodiments, the pressureinside a fiber producing system may be at or about ambient pressure. Inother embodiments, the pressure inside a fiber producing system may begreater than ambient pressure. For example the pressure inside a fiberproducing system may range from about 800 mm Hg to about 4 atmospheres(atm) of pressure, or any range derivable therein.

In certain embodiments, the fiber is created in an environment of 0-100%humidity, or any range derivable therein. The temperature of theenvironment in which the fiber is created may vary widely. In certainembodiments, the temperature of the environment in which the fiber iscreated can be adjusted before operation (e.g., before rotating) using aheat source and/or a cooling source. Moreover, the temperature of theenvironment in which the fiber is created may be adjusted duringoperation using a heat source and/or a cooling source. The temperatureof the environment may be set at sub-freezing temperatures, such as −20°C., or lower. The temperature of the environment may be as high as, forexample, 2500° C.

The material employed may include one or more components. The materialmay be of a single phase (e.g., solid or liquid) or a mixture of phases(e.g., solid particles in a liquid). In some embodiments, the materialincludes a solid and the material is heated. The material may become aliquid upon heating. In another embodiment, the material may be mixedwith a solvent. As used herein a “solvent” is a liquid that at leastpartially dissolves the material. Examples of solvents include, but arenot limited to, water and organic solvents. Examples of organic solventsinclude, but are not limited to: hexanes, ether, ethyl acetate, acetone,dichloromethane, chloroform, toluene, xylenes, petroleum ether,dimethylsulfoxide, dimethylformamide, or mixtures thereof. Additives mayalso be present. Examples of additives include, but are not limited to:thinners, surfactants, plasticizers, or combinations thereof.

The material used to form the fibers may include at least one polymer.Polymers that may be used include conjugated polymers, biopolymers,water soluble polymers, and particle infused polymers. Examples ofpolymers that may be used include, but are not limited topolypropylenes, polyethylenes, polyolefins, polystyrenes, polyesters,fluorinated polymers (fluoropolymers), polyamides, polyaramids,acrylonitrile butadiene styrene, nylons, polycarbonates, beta-lactams,block copolymers or any combination thereof. The polymer may be asynthetic (man-made) polymer or a natural polymer. The material used toform the fibers may be a composite of different polymers or a compositeof a medicinal agent combined with a polymeric carrier. Specificpolymers that may be used include, but are not limited to chitosan,nylon, nylon-6, polybutylene terephthalate (PBT), polyacrylonitrile(PAN), poly(lactic acid) (PLA), poly(lactic-co-glycolic acid) (PLGA),polyglycolic acid (PGA), polyglactin, polycaprolactone (PCL), silk,collagen, poly(methyl methacrylate) (PMMA), polydioxanone, polyphenylenesulfide (PPS); polyethylene terephthalate (PET), polytetrafluoroethylene(PTFE), polyvinylidene fluoride (PVDF), polypropylene (PP), polyethyleneoxide (PEO), acrylonitrile butadiene, styrene (ABS), andpolyvinylpyrrolidone (PVP).

In another embodiment, the material used to form the fibers may be ametal, ceramic, or carbon-based material. Metals employed in fibercreation include, but are not limited to, bismuth, tin, zinc, silver,gold, nickel, aluminum, or combinations thereof. The material used toform the fibers may be a ceramic such as alumina, titania, silica,zirconia, or combinations thereof. The material used to form the fibersmay be a composite of different metals (e.g., an alloy such as nitonol),a metal/ceramic composite or a ceramic oxides (e.g., PVP withgermanium/palladium/platinum).

The fibers that are created may be, for example, one micron or longer inlength. For example, created fibers may be of lengths that range fromabout 1 μm to about 50 cm, from about 100 μm to about 10 cm, or fromabout 1 mm to about 1 cm. In some embodiments, the fibers may have anarrow length distribution. For example, the length of the fibers may bebetween about 1 μm to about 9 μm, between about 1 mm to about 9 mm, orbetween about 1 cm to about 9 cm. In some embodiments, when continuousmethods are performed, fibers of up to about 10 meters, up to about 5meters, or up to about 1 meter in length may be formed.

In certain embodiments, the cross-section of the fiber may be circular,elliptical or rectangular. Other shapes are also possible. The fiber maybe a single-lumen fiber or a multi lumen fiber.

In another embodiment of a method of creating a fiber, the methodincludes: spinning material to create the fiber; where, as the fiber isbeing created, the fiber is not subjected to an externally-appliedelectric field or an externally-applied gas; and the fiber does not fallinto a liquid after being created.

Fibers discussed herein are a class of materials that exhibit an aspectratio of at least 100 or higher. The term “microfiber” refers to fibersthat have a minimum diameter in the range of 10 microns to 700nanometers, or from 5 microns to 800 nanometers, or from 1 micron to 700nanometers. The term “nanofiber” refers to fibers that have a minimumdiameter in the range of 500 nanometers to 1 nanometer; or from 250nanometers to 10 nanometers, or from 100 nanometers to 20 nanometers.

While typical cross-sections of the fibers are circular or elliptic innature, they can be formed in other shapes by controlling the shape andsize of the openings in a fiber producing device (described below).Fibers may include a blending of multiple materials. Fibers may alsoinclude holes (e.g., lumen or multi-lumen) or pores. Multi-lumen fibersmay be achieved by, for example, designing one or more exit openings topossess concentric openings. In certain embodiments, such openings mayinclude split openings (that is, wherein two or more openings areadjacent to each other; or, stated another way, an opening possesses oneor more dividers such that two or more smaller openings are made). Suchfeatures may be utilized to attain specific physical properties, such asthermal insulation or impact absorbance (resilience). Nanotubes may alsobe created using methods and apparatuses discussed herein.

Fibers may be analyzed via any means known to those of skill in the art.For example, Scanning Electron Microscopy (SEM) may be used to measuredimensions of a given fiber. For physical and materialcharacterizations, techniques such as differential scanning calorimetry(DSC), thermal analysis (TA) and chromatography may be used.

In particular embodiments, a fiber of the present fibers is not alyocell fiber. Lyocell fibers are described in the literature, such asin U.S. Pat. Nos. 6,221,487, 6,235,392, 6,511,930, 6,596,033 and7,067,444, each of which is incorporated herein by reference.

In one embodiment, microfibers and nanofibers may be producedsubstantially simultaneously. Any fiber producing device describedherein may be modified such that one or more openings has a diameterand/or shape that produces nanofibers during use, and one or moreopenings have a diameter and/or shape that produces microfibers duringuse. Thus, a fiber producing device, when rotated will eject material toproduce both microfibers and nanofibers. In some embodiments, nozzlesmay be coupled to one or more of the openings. Different nozzles may becoupled to different openings such that the nozzles designed to createmicrofibers and nozzles designed to create nanofibers are coupled to theopenings. In an alternate embodiment, needles may be coupled (eitherdirectly to the openings or via a needle port). Different needles may becoupled to different openings such that needles designed to createmicrofibers and needles designed to create nanofibers are coupled to theopenings. Production of microfibers and nanofibers substantiallysimultaneously may allow a controlled distribution of the fiber size tobe achieved, allowing substantial control of the properties of productsultimately produced from the microfiber/nanofiber mixture.

After production of fibers is completed, it is desirable to clean thefiber producing device to allow reuse of the system. Generally, it iseasiest to clean a fiber producing device when the material is in aliquid state. Once the material reverts to a solid, cleaning may bedifficult, especially cleaning up small diameter nozzles and or needlescoupled to the fiber producing device. The difficulty, especially withmelt spinning, is that cleanup may also be difficult when the device isat an elevated temperature, especially if the fiber producing deviceneeds to be cooled prior to handling for clean up. In some embodiments,a purge system may be couplable to fiber producing device when the fiberproducing device is heated. A purge system may provide an at leastpartial seal between the purge system and the body of a fiber producingdevice such that a gas may be directed into the body, through the purgesystem, to create a pressurized gas inside of the body. The purgesystem, in some embodiments, includes a sealing member couplable to thebody, a pressurized gas source, and a conduit coupling the pressurizedgas source to the sealing member.

Purge system may be coupled to an opening of the fiber producing deviceused to feed material into the body of the fiber producing device. In anembodiment, a purge system 3110 is coupled to body 3120 of a fiberproducing device 3100, as depicted in FIG. 31. The purge system iscouplable to a body 3102 of the fiber producing device. Purge system3110 includes a sealing member 3112 coupled to a gas transfer member3114. When coupled to body, sealing member 3112 may form a seal betweenan opening (depicted in FIG. 7) of fiber producing device 3100 and thepurge system sealing member 3112 such that pressurized gas 3115 may besent into the fiber producing device. During use, gas transfer membermay be coupled to a pressurized gas source through a conduit. Thepressurized gas may force any material disposed in an opening out of theopenings (and any devices coupled to the openings) to clear material outthe fiber producing device. All of the material in the fiber producingdevice may be forced out of the openings such that the fiber producingdevice is substantially clear of material and ready for the next use.Alternatively, material may remain in the fiber producing device afterpurging, however, the material in the openings and any devices coupledto the opening may be cleared out. In this manner the openings, whichare generally more difficult to clean, are cleaned prior to thediscontinuation of fiber production.

In one embodiment, a material feed inlet is coupled to a fiber producingdevice such that material may be substantially continuously fed to thefiber producing device (as shown in FIG. 25). Material feed line may becoupled to a material supply source. In an embodiment, material feedinlet may also be coupled to a purge gas source. One or more valves maybe disposed between the purge gas source, the supply source and thematerial feed inlet to allow switching between the material and thepurge gas. In an embodiment, material may pass through the materialinlet into the fiber producing device during fiber production. Whenfiber production is to be discontinued, the vales(s) may be switched tooallow purge gas to pass through the material inlet and into the fiberproducing device, driving at least some of the material out of theopenings and any devices coupled to the openings. One or more of thevalves may be coupled to a controller that automatically performs apurge during a programmed or user selected shutdown of the system.

Another embodiment of a fiber producing system is depicted in FIG. 33.Fiber producing system 3300 includes a fiber producing device 3310.Fiber producing device includes a body 3312 and a coupling member 3314.In one embodiment, body 3312 comprises a first member 3314 and a secondmember 3316 coupled together. Alternatively, body 3312 may be a singleunitary member. First member 3314 and second member 3316 together definean internal cavity 3318. One or more openings 3320 extend through thebody through which material disposed in the body may pass through duringuse. One or more outlet elements (e.g., nozzles, needles, needle portsor outlet conduits) may be coupled to one or more openings 3320. Asdiscussed previously, internal cavity of the body may include angled orrounded walls to help direct material disposed in internal cavity 3318of body 3312 toward openings 3320.

Coupling member 3330 may be an elongated member extending from the body.In one embodiment, coupling member 3330 is coupled to the second member3316 of body 3312 and extends away from the second member throughinternal cavity 3318. Coupling member 3330 may be used to couple fiberproducing device 3310 to a coupling element 3342 of a driver 3340 (e.g.,a chuck coupler or a universal threaded joint of the driver).Alternatively, coupling member may be a receiver which will accept anelongated member from a driver (e.g., the coupling member may be a chuckor a universal threaded joint). Coupling element 3342 of driver mayinteract with coupling member 3330 of the fiber producing device toallow the coupling member to be adjustably positionable in the couplingelement such that the distance between the fiber producing device andthe driver is alterable. This may be useful for applications where theproduced fibers are delivered to a substrate positioned below the fiberproducing device. Assuming the substrate and driver are at a fixeddistance from each other, altering the vertical distance between thefiber producing device and the driver also alters the vertical distancebetween an underlying substrate and the fiber producing device. Beingable to alter the distance between the underlying substrate and thefiber producing device allows the fiber deposition patterns to bealtered and customized for different substrates.

Fiber producing system 3300 may include a driver 3340 coupled tocoupling member 3330. Driver 3340 is positioned above fiber producingdevice 3330 when the fiber producing device is coupled to the driver.Driver 3330 is capable of rotating fiber producing device 3310 duringuse. Suitable drivers include commercially available variable electricmotors, such as a brushless DC motor.

Fiber producing system 3330 may further include a material deliverysystem 3350. Material delivery system 3350 includes a material storagecontainer 3352, a pump 3354, and a conduit 3356 for conducting a liquidmixture to fiber producing device 3310. A mixture of material in aliquid is stored in storage container 3352. A mixture of material in aliquid may be formed by dissolving the material in a suitable solvent toform a solution of the material. The mixture of material in a liquid istransferred to fiber producing device 3352 using pump 3354 coupled tostorage container 3352. Pump 3352 collects the liquid mixture andcreates a flow of liquid material through conduit 3356. The liquidmixture enters fiber producing device 3310 from conduit 3356 through anopening 3313 formed in the fiber producing device. A fluid level sensor3358 is optically coupled to the liquid mixture disposed in the fiberproducing device. Fluid sensor 3358 provides a measurement of the amountof fluid disposed in the fiber producing device. During use, the pumpflow rate may be adjusted based on the amount of fluid in the fiberproducing device. In one embodiment, material delivery system 3350substantially continuously delivers material to fiber producing device3310 while the fiber producing device is rotating. Positioning ofconduit 3356 outside of the fiber producing device allows continuousdelivery of material while the fiber producing device is rotating.

Driver 3340 may be mounted to arm 3360. In one embodiment, arm 3360 maybe coupled to a support (not shown). Arm 3360 may be coupled to asupport such that the arm is movable with respect to the support. Forexample, arm 3360 may allow driver 3340 and the coupled fiber producingdevice 3310 (referred to as the “driver/fiber producing deviceassembly”) to be moved (e.g., swung) away from the substrate to allowmaintenance to be performed on the fiber producing device (e.g.,changing the fiber producing device, purging the fiber producing device,etc. Arm 3360 may also allow the horizontal position of the driver/fiberproducing device assembly to be altered. In an embodiment, arm 3360allows the driver/fiber producing device assembly to be moved along ahorizontal fixed path. This allows the placement of the driver/fiberproducing device assembly to be altered with respect to an underlyingsubstrate. In some embodiments, a motor may be coupled to thedriver/fiber producing device assembly to allow automated movement ofthe driver/fiber producing device assembly with respect to thesubstrate.

In one embodiment, the pattern of fibers deposited by a fiber producingdevice 3310 in an inverted configuration, as described with respect toFIG. 33, may not be sufficient to provide uniform coverage of theunderlying substrate. In order to improve coverage, the driver/fiberproducing device assembly may be horizontally moved with respect to thesubstrate to provide a more even coverage to the underlying substrate.For example, arm may allow the driver/fiber producing device assembly tobe moved along a fixed horizontal path. When the substrate is positionedbelow the fiber producing device, fiber production may be started andthe driver/fiber producing device assembly may be horizontally moved toproduce a more homogenous deposition of fibers on the substrate. Thehorizontal movement of the driver/fiber producing device assembly may becoordinated with the movement of the underlying substrate through thefiber deposition system. In an alternate embodiment, the arm may beconfigured to rotate the driver/fiber producing device assembly withrespect to the substrate. Rotation of the driver/fiber producing deviceassembly may allow a more even distribution of the fibers in thesubstrate.

In some embodiments, fiber producing device may be heated. One or moreheating devices 3370 and 3372, may be thermally coupled to fiberproducing device 3310. In some embodiments, a heating device 3370 may bering shaped heating device to allow the coupling member to extendthrough the heating device. Heating device 3372 may be a planarsubstrate disposed below the fiber producing device or ring shaped. Insome embodiments, heating devices 3370 and 3372 may have a diameter thatis less than the diameter of fiber producing device 3310. It has beengenerally found that during production of fibers, the produced fibersmay be drawn to the heat from the heating devices if the fibers come toclose to such devices. By reducing the diameter of the heating devicesto be less then the diameter of the fiber producing devices, the loss offiber due to contact with the heating devices is minimized. Furtherdetails regarding heating devices are described with respect to theheating device depicted in FIG. 39.

Another embodiment of a fiber producing system is depicted in FIG. 34.The fiber producing system depicted in FIG. 34 is similar to the systemdepicted in FIG. 33. The system in FIG. 34, however, is configured foruse in melt spinning procedures, while the system of FIG. 33 isconfigured for use in solution spinning procedures. To accommodate meltspinning processes, the material delivery system 3350 includes amaterial storage container 3380 and an extruder 3382. Solid material isstored in material storage container 3380 and transferred to extruder3382. Extruder 3382 receives material from material storage container3380 and melts the material producing a melt. The melt is transferred tometered melt pump 3385 that meters and pumps the molten material thoughthe conduit 3386 to the fiber producing device. Conduit 3386 is formedof a material capable of transporting the heated material from theextruder to the fiber producing device. In some embodiments, conduit3386 is at least partially surrounded by insulation 3384 to inhibitcooling of the heated material as it is transferred to the fiberproducing device. Heating devices 3370 and 3372 are used to keep thefiber producing device at a sufficient temperature to maintain thematerial in a melted state.

In an alternate embodiment, extruder 3382 may be replaced with amaterial feed hopper. Material feed hopper may be used to channel asolid material disposed in material storage container 3380 directly intothe fiber producing device. The fiber producing device may be heated tomelt at least a portion of the solid material that is transferred fromthe material storage container into the fiber producing device. Heatingdevices, as described previously, may be used to heat the fiberproducing device prior to or after the solid material is placed in thefiber producing device. In this manner, the use of an extruder andinsulated conduits may be avoided, reducing the energy requirements ofthe system.

A top driven fiber producing system is particularly useful fordepositing fibers onto a substrate. An embodiment of a system fordepositing fibers onto a substrate is shown in FIG. 35. Substratedeposition system 3500 includes a deposition system 3600 and a substratetransfer system 3550. Deposition system 3600 includes a fiber producingsystem 3610, as described herein. Deposition system produces and directsfibers produced by a fiber producing device toward a substrate 3520disposed below the fiber producing device during use. Substrate transfersystem moves a continuous sheet of substrate material through thedeposition system.

Deposition system 3600, in one embodiment, includes a top mounted fiberproducing device 3610. During use, fibers produced by fiber producingdevice 3610 are deposited onto substrate 3520. A schematic diagram ofdeposition system 3600 is depicted in FIG. 36. Fiber deposition systemmay include one or more of: a vacuum system 3620, an electrostatic plate3630, and a gas flow system 3640. A vacuum system produces a region ofreduced pressure under substrate 3520 such that fibers produced by fiberproducing device 3610 are drawn toward the substrate due to the reducedpressure. Alternatively, one or more fans may be positioned under thesubstrate to create an air flow through the substrate. Gas flow system3640 produces a gas flow 3642 that directs fibers formed by the fiberproducing device toward the substrate. Gas flow system may be apressurized air source or one or more fans that produce a flow of air(or other gase). The combination of vacuum and air flow systems are usedto produce a “balanced air flow” from the top of the deposition chamberthrough the substrate to the exhaust system by using forced air (fans,pressurized air) and exhaust air (fans, to create an outward flow) andbalancing and directing the airflow to produce a fiber deposition fielddown to the substrate. Deposition system 3600 includes substrate inlet3614 and substrate outlet 3612.

An electrostatic plate 3630 is also positioned below substrate 3520. Theelectrostatic plate is a plate capable of being charged to apredetermined polarity. Typically, fibers produced by the fiberproducing device have a net charge. The net charge of the fibers may bepositive or negative, depending on the type of material used. To improvedeposition of charged fibers, an electrostatic plate may be disposedbelow substrate 3520 and be charged to an opposite polarity as theproduced fibers. In this manner, the fibers are attracted to theelectrostatic plate due to the electrostatic attraction between theopposite charges. The fibers become embedded in the substrate as thefibers move toward the electrostatic plate.

A pressurized gas producing and distribution system may be used tocontrol the flow of fibers toward a substrate disposed below the fiberproducing device. During use fibers produced by the fiber producingdevice are dispersed within the deposition system. Since the fibers arecomposed primarily of microfibers and/or nanofibers, the fibers tend todisperse within the deposition system. The use of a pressurized gasproducing and distribution system may help guide the fibers toward thesubstrate. In one embodiment, a pressurized gas producing anddistribution system includes a downward gas flow device 3640 and alateral gas flow device 3645. Downward gas flow device 3640 ispositioned above or even with the fiber producing device to facilitateeven fiber movement toward the substrate. One or more lateral gas flowdevices 3645 are oriented perpendicular to or below the fiber producingdevice. In some embodiment, lateral gas flow devices 3645 have an outletwidth equal to the substrate width to facilitate even fiber depositiononto substrate. In some embodiments, the angle of the outlet of one ormore lateral gas flow devices 3645 may be varied to allow better controlof the fiber deposition onto the substrate. Each lateral gas flowdevices 3645 may be independently operated.

During use of the deposition system, fiber producing device 3610 mayproduce various gasses due to evaporation of solvents (during solutionspinning) and material gasification (during melt spinning). Such gasses,if accumulated in the deposition system may begin to effect the qualityof the fiber produced. In some embodiment, the deposition systemincludes an outlet fan 3650 to remove gasses produced during fiberproduction from the deposition system.

Substrate transfer system 3550, in one embodiment, is capable of movinga continuous sheet of substrate material through the deposition system.In one embodiment, substrate transfer system 3550 includes a substratereel 3552 and a take up reel system 3554. During use, a roll ofsubstrate material is placed on substrate reel 3552 and threaded throughdeposition system 3600 to the substrate take up reel system 3554. Duringuse, substrate take up reel system 3554 rotates, pulling substratethrough deposition system at a predetermined rate. In this manner, acontinuous roll of a substrate material may be pulled through fiberdeposition system.

In some embodiments, it may be difficult for a single fiber producingdevice to produce a sufficient amount of fibers to provide a desiredlevel of fibers to an entire substrate. In order to ensure adequate andeven coverage of fibers on a substrate, a substrate deposition systemmay include two or more fiber producing devices, as depicted in FIG. 37.A fiber deposition system 3700 may include two or more fiber producingdevices 3710 coupled to a driver unit 3720. Driver unit is coupled tofiber producing devices 3710. In one embodiment, driver unit 3720includes a plurality of drivers, each driver being coupled to a fiberproducing device 3710. The drive unit includes a controller capable ofindividually operating each of the drive units such that two or more ofthe fiber producing devices substantially simultaneously produce fibers.In an alternate embodiment, driver unit includes a single driver thatsimultaneously operates all of the fiber producing devices coupled tothe driver unit. In such an embodiment, all of the fiber producingdevices substantially simultaneously produce fibers to ensure completecoverage of the underlying substrate 3730.

An embodiment of a fiber producing device is depicted in FIGS. 38A-C.Fiber producing device 3800 includes a body comprising a first member3810 (FIG. 38A) and a second member 3820 (FIG. 38B). First member 3810includes a first member coupling surface 3812. First member couplingsurface 3812 includes one or more grooves 3814 extending along the widthof the first member coupling surface. Second member 3820 includes asecond member coupling surface 3822 and a coupling member 3828. Secondmember coupling surface 3822 comprising one or more grooves 3824extending along the width of the second member coupling surface.Coupling member 3828 may be used to couple the body to a driver of afiber producing system.

The body is formed by coupling first member 3810 to second member 3820.To couple the first and second members, first member coupling surface3812 is contacted with second member coupling surface 3822. One or morefasteners 3830 may be used to secure the first member and second membertogether. When the first member coupling surface is coupled to thesecond member coupling surface to form the body, the first member andthe second member together define an internal cavity of the body. In oneembodiment, fasteners 3830 have an effect on the pattern of fiberproduced by the fiber producing device. For example, the head of afastener produces external gas currents due to the high speed ofrotation of the fiber producing device. Additional components may beadded on either side of the body or incorporated directly onto thesurface of the body to produce external gas currents. These external gascurrents can effect the pattern of fibers produced. The pattern offibers produced by the fiber producing device may be altered by usingfasteners having different head configurations. Alternatively, theposition of fasteners may be altered to change the fiber depositionpattern. For example, the one or more fasteners may be left out ofexisting holes. Alternatively, the body may include a plurality ofholes. The pattern of fibers produced by the fiber producing device maybe altered by changing which of the plurality of holes are used tocouple the first and second members together. In another embodiment,.The height of the fasteners may be altered by loosing and or tighteningthe fasteners. Thus the height of the head of one or more fasteners maybe varied to alter the pattern of fibers produced by the fiber producingdevice.

In some embodiments, it is desirable that grooves 3814 of the firstmember are substantially aligned with groves 3824 of the second member.When the grooves are aligned, the grooves together form one or moreopenings 3850 extending from the interior cavity to an outer surface ofthe body. During use, rotation of the body material disposed in theinternal cavity of the body is ejected through one or more openings 3850to produce microfibers and/or nanofibers. Material may be placed intothe body of fiber producing through a first member opening 3828 formedin first member 3810. In one embodiment, first member is ring shaped andmaterial is added to the internal cavity through a central opening ofthe ring shaped first member.

In order to ensure proper alignment of the first member with the secondmember, the first member may include a first alignment element 3816disposed on the first coupling member surface 3812. The second membermay include a second alignment element 3826 disposed on the secondmember coupling surface 3822. First alignment element 3816 couples withsecond alignment element 3826 when first member 3810 is properly alignedwith second member 3820. This may help to ensure that grooves 3814 and3824 are properly aligned. In one embodiment, one of the first or secondalignment elements includes a projection extending form the couplingsurface, and the other of the first or second alignment elementsincludes an indentation complementary to the projection.

In an embodiment, the first alignment element may be a first alignmentring 3816 disposed on the first coupling member surface 3812. The secondmember may include a second alignment ring 3826 disposed on the secondmember coupling surface 3822. First alignment ring 3816 interlocks withsecond alignment ring 3826 when first member 3810 is properly alignedwith second member 3820. The interlocking first and second rings centerthe first member and second member with each other. In one embodiment,first and second rings interlock with each other on an angle so that thefirst and second members are centered to one another. Alignment isfurther insured by the use of a projection 3840 formed in the firstmember which fits into a suitable indentation 3845 formed in the secondmember. Projection 3840 and indentation 3845 help ensure that the firstand second members are coupled in the same rotational position such thatthe grooves of the first and second members are aligned.

In an embodiment, where the fiber producing device is coupled to adriver positioned above the fiber producing device, the coupling memberextends through the internal cavity defined by the first and secondmembers and through the first member. Alternatively, where the fiberproducing device is coupled to a driver positioned below the fiberproducing device, the coupling member is coupled to an outer surface ofthe second member, extending away from the second member.

An embodiment of a multiple layer fiber producing device is depicted inFIG. 38D. Fiber producing device 3800 includes a body comprising a firstmember 3810, a second member 3820, and a third member 3830. It should beunderstood that while three members are shown, any number of members maybe coupled together to form a multiple layer fiber producing device. Thebody is formed by coupling first member 3810 to second member 3820 andsecond member to third member 3830. Second member includes a secondmember coupling surface and an additional coupling surface, disposed onthe side opposite to the second member coupling surface. Both the secondmember coupling surface and the second member additional couplingsurface include grooves extending along the width of the respectivesurfaces. First and second members couple together by contacting firstmember coupling surface with the second member coupling surface. Groovesof the first member are substantially aligned with groves of the secondmember to form one or more openings 3850 extending from the interiorcavity to an outer surface of the body. Second and third members alsocouple together by contacting the second member additional couplingsurface with the third member coupling surface. Grooves of the secondmember additional coupling surface are substantially aligned with grovesof the third member coupling surface to form one or more openings 3850extending from the interior cavity to an outer surface of the body.

During use, material disposed in the internal cavity of the body isejected through one or more openings 3850 and one or more openings 3855to produce microfibers and/or nanofibers. Material may be placed intothe body of fiber producing through a first member opening formed infirst member 3828. In one embodiment, material is added to the internalcavity through a central opening of the first member.

An embodiment of a heating device 3900 is depicted in FIG. 39. One ormore heating elements 3910 are coupled to a heating device substrate3920. Heating substrate 3920 is formed of a thermally conductivematerial (e.g., stainless steel, iron, etc.). Heating elements 3910 mayprovide heat to heat substrate 3920. Substrate 3920 is thermally coupledto one or more components of a fiber producing system (e.g., a fiberproducing device). In one embodiment, heating elements 3910 may becartridge heaters that are disposed within substrate 3920. For example,one or more openings may be formed in substrate 3920 and the cartridgeheaters disposed in the openings. During use, an electric current may beapplied to one or more of the cartridge heaters to heat the substrate.While the heating device is depicted as having a ring shaped substrate,it should be understood that other shapes may be used.

In an alternate embodiments, a heating device used to heat a fiberproducing device is a radiant heater. An infrared heater is an exampleof a radiant heater that may be used to heat a fiber producing device.

An embodiment of a fiber producing device is depicted in FIG. 40. Fiberproducing device 4000 includes a body comprising a first member 4010 anda second member 4020. The body is formed by coupling first member 4010to second member 4020. First and second members couple together bycontacting first member coupling surface with second member couplingsurface. In some embodiments, it is desirable that grooves of the firstmember are substantially aligned with groves of the second member. Whenthe grooves are aligned, the grooves together form one or more openings4050 extending from the interior cavity to an outer surface of the body.During use, rotation of the body material disposed in the internalcavity of the body is ejected through one or more openings 4050 toproduce microfibers and/or nanofibers. Material may be placed into thebody of fiber producing through a first member opening formed in firstmember 4010. In one embodiment, first member is ring shaped and materialis added to the internal cavity through a central opening of the ringshaped first member.

One or more fasteners 4030 may be used to secure the first member andsecond member together. When the first member coupling surface iscoupled to the second member coupling surface to form the body, thefirst member and the second member together define an internal cavity ofthe body. One or more channels 4028 may be added on either side of thebody surrounding openings 4050 and extending away from the openings.Channels 4028 help alter the external gas currents produced when thespinneretet is spinning. These external gas currents can effect thepattern of fibers produced and/or the size of the fibers produced. Thepattern of fibers produced by the fiber producing device may be alteredby using channels having different sizes and/or shapes. In someembodiments, channels 4028 are concave channels that allow the fiberproducing material ejected from the openings to run along the channeland be ejected at an angle away from the body.

Fiber producing devices may be formed in different shapes. Non-limitingexamples of fiber producing devices having alternate shapes are depictedin FIGS. 41A-B and FIG. 42. In an embodiment depicted in FIG. 41A, fiberproducing device 4100 includes a body that is in the form of a star. Thebody of the fiber producing device is composed of a first member 4110and a second member 4120, as depicted in FIG. 41B. The body is formed bycoupling first member 4110 to second member 4120. First and secondmembers couple together by contacting first member coupling surface withsecond member coupling surface. In some embodiments, it is desirablethat grooves of the first member are substantially aligned with grovesof the second member. When the grooves are aligned, the grooves togetherform one or more openings 4150 extending from the interior cavity to anouter surface of the body. During use, rotation of the body materialdisposed in the internal cavity of the body is ejected through one ormore openings 4150 to produce microfibers and/or nanofibers. Materialmay be placed into the body of fiber producing through a first memberopening formed in first member 3810. In one embodiment, material isadded to the internal cavity through a central opening 4140 of the firstmember. In some embodiments, each arm of fiber producing device 4100 mayhave an aerodynamic profile. The use of an aerodynamic profile mayreduce drag forces on the fiber producing device as the device is spunduring use. Additionally, the profile of the arms may be adjusted tocontrol the physical properties of the fibers being produced.

In another embodiment, a gear shaped fiber producing device, as depictedin FIG. 42 may be used to produce nanofibers and/or microfibers. Gearshaped fiber producing device 4200 may be formed from a single unitarydevice, or from two or more sperate pieces that are coupled together ashad been described above. Fiber producing device 4200 includes aplurality of protruding segments 4230 extending from central body 4210.Each segment 4230 is defined by sidewalls 4232 and 4234. Sidewalls 4232are substantially straight, while sidewalls 4234 are curved. Thesegments 4230 are positioned such that the straight sidewalls 4232 of asegment are positioned across from the curved sidewall of an adjacentsegment 4234. Thus a gap is formed between the segments having a curvedand straight boundary.

In contrast to other fiber producing devices, openings 4250 are formedin between the protruding segments 4230, rather than at the end of thesegments. During use, material disposed in the body of fiber producingdevice 4200 is ejected through openings 4250. When the fiber producingdevice is rotating, the material exits openings 4250 and is carried tothe curved sidewalls 4234. The material runs along the curved sidewallsand is ejected from the fiber producing device. The amount of arc oncurved sidewalls 4234 may be adjusted to alter the size and/or directionthat the fibers are produced.

Applications

Microfibers and nanofibers produced using any of the devices and methodsdescribed herein may be used in a variety of applications. Some generalfields of use include, but are not limited to: food, materials,electrical, defense, tissue engineering, biotechnology, medical devices,energy, alternative energy (e.g., solar, wind, nuclear, andhydroelectric energy); therapeutic medicine, drug delivery (e.g., drugsolubility improvement, drug encapsulation, etc.); textiles/fabrics,nonwoven materials, filtration (e.g., air, water, fuel, semiconductor,biomedical, etc); automotive; sports; aeronautics; space; energytransmission; papers; substrates; hygiene; cosmetics; construction;apparel, packaging, geotextiles, thermal and acoustic insulation.

Some products that may be formed using microfibers and/or nanofibersinclude but are not limited to: filters using charged nanofiber and/ormicrofiber polymers to clean fluids; catalytic filters using ceramicnanofibers (“NF”); carbon nanotube (“CNT”) infused nanofibers for energystorage; CNT infused/coated NF for electromagnetic shielding; mixedmicro and NF for filters and other applications; polyester infused intocotton for denim and other textiles; metallic nanoparticles or otherantimicrobial materials infused onto/coated on NF for filters; wounddressings, cell growth substrates or scaffolds; battery separators;charged polymers or other materials for solar energy; NF for use inenvironmental clean-up; piezoelectric fibers; sutures; chemical sensors;textiles/fabrics that are water & stain resistant, odor resistant,insulating, self-cleaning, penetration resistant, anti-microbial,porous/breathing, tear resistant, and wear resistant; force energyabsorbing for personal body protection armor; construction reinforcementmaterials (e.g., concrete and plastics); carbon fibers; fibers used totoughen outer skins for aerospace applications; tissue engineeringsubstrates utilizing aligned or random fibers; tissue engineering Petridishes with aligned or random nanofibers; filters used in pharmaceuticalmanufacturing; filters combining microfiber and nanofiber elements fordeep filter functionality; hydrophobic materials such as textiles;selectively absorbent materials such as oil booms; continuous lengthnanofibers (aspect ratio of more than 1,000 to 1); paints/stains;building products that enhance durability, fire resistance, colorretention, porosity, flexibility, anti microbial, bug resistant, airtightness; adhesives; tapes; epoxies; glues; adsorptive materials;diaper media; mattress covers; acoustic materials; and liquid, gas,chemical, or air filters.

Fibers may be coated after formation. In one embodiment, microfibersand/or nanofibers may be coated with a polymeric or metal coating.Polymeric coatings may be formed by spray coating the produced fibers,or any other method known for forming polymeric coatings. Metal coatingsmay be formed using a metal deposition process (e.g., CVD).

In this patent, certain U.S. patents, U.S. patent applications, andother materials (e.g., articles) have been incorporated by reference.The text of such U.S. patents, U.S. patent applications, and othermaterials is, however, only incorporated by reference to the extent thatno conflict exists between such text and the other statements anddrawings set forth herein. In the event of such conflict, then any suchconflicting text in such incorporated by reference U.S. patents, U.S.patent applications, and other materials is specifically notincorporated by reference in this patent.

Further modifications and alternative embodiments of various aspects ofthe invention will be apparent to those skilled in the art in view ofthis description. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the general manner of carrying out the invention. It is to beunderstood that the forms of the invention shown and described hereinare to be taken as examples of embodiments. Elements and materials maybe substituted for those illustrated and described herein, parts andprocesses may be reversed, and certain features of the invention may beutilized independently, all as would be apparent to one skilled in theart after having the benefit of this description of the invention.Changes may be made in the elements described herein without departingfrom the spirit and scope of the invention as described in the followingclaims.

1-1015. (canceled)
 1016. A device for use in a microfiber and/ornanofiber producing system, the device comprising: a body comprising oneor more openings and a coupling member, wherein the body is configuredto receive material to be produced into a fiber; and one or more outletelements coupled to one or more of the openings, wherein the one or moreoutlet elements comprise an outer conduit and an inner conduit, whereinthe inner conduit is sized and positioned inside of the outer conduitsuch that material flows through the inner conduit and the outer conduitduring use; wherein, during use, rotation of the body coupled to thedriver causes material in the body to be ejected through the innerconduit and outer conduit of the outlet elements to produce coaxialmicrofibers and/or nanofibers.
 1017. The device of claim 1016, whereinthe outlet elements are removably couplable to the body.
 1018. Thedevice of claim 1016, wherein the body comprises a locking system usedto couple one or more outlet elements to the openings, wherein thelocking system locks the coupled outlet element in a predeterminedorientation with respect to the body.
 1019. The device of claim 1016,further comprising one or more outlet conduits coupling one or more ofthe outlet elements to one or more openings.
 1020. The device of claim1019, wherein one or more outlet conduits have a length of at leastabout 10 mm.
 1021. The device of claim 1016, wherein the body comprisesone or more sidewalls and a top, together defining an internal cavity,wherein one or more openings extend through a sidewall of the body,communicating with the internal cavity.
 1022. The device of claim 1016,wherein the body comprises one or more sidewalls and a top, togetherdefining an internal cavity, and wherein an interior surface of thesidewall is angled from a bottom wall toward one or more of theopenings.
 1023. The device of claim 1016, wherein the body comprises oneor more sidewalls and a top, together defining an internal cavity, andwherein an interior surface of the sidewall is rounded from a bottomwall toward one or more of the openings.
 1024. The device of claim 1016,wherein the body comprises one or more sidewalls and a top, togetherdefining an internal cavity, and wherein an interior surface of thesidewall has an oval shape such that the long axis of the oval interiorsidewall is in alignment with one or more of the openings.
 1025. Amicrofiber and/or nanofiber producing system comprising: a fiberproducing device comprising: a body comprising one or more openings anda coupling member, wherein the body is configured to receive material tobe produced into a fiber; and one or more outlet elements coupled to oneor more of the openings, wherein the one or more outlet elementscomprise an outer conduit and an inner conduit, wherein the innerconduit is sized and positioned inside of the outer conduit such thatmaterial flows through the inner conduit and the outer conduit duringuse; and a driver capable of rotating the fiber producing device,wherein the fiber producing device is couplable to the driver throughthe coupling member; and wherein, during use, rotation of the fiberproducing device coupled to the driver causes material in the body to beejected through the inner conduit and outer conduit of the outletelements to produce coaxial microfibers and/or nanofibers. 1026-1033.(canceled)
 1034. The system of claim 1025, wherein the driver ispositioned above the fiber producing device, when the fiber producingdevice is coupled to the driver.
 1035. The system of claim 1025, furthercomprising a heating device thermally coupled to the fiber producingdevice.
 1036. The system of claim 1035, wherein the heating devicecomprises one or more heating elements coupled to a ring-shapedsubstrate.
 1037. The system of claim 1035, wherein the heating devicecomprises an infrared radiant heater.
 1038. The system of claim 1025,wherein the fiber producing device is enclosed in a chamber, and whereinthe environment inside the chamber is controllable.
 1039. The system ofclaim 1025, wherein the driver is capable of rotating the fiberproducing device at speeds of greater than about 1000 rpm.
 1040. Thesystem of claim 1025, further comprising a collection system surroundingat least a portion of the fiber producing device, wherein fibersproduced during use are at least partially collected on the collectionsystem.
 1041. The system of claim 1040, wherein the collection systemcomprises one or more collection elements coupled to a collectionsubstrate, wherein the one or more collection elements at leastpartially surround the fiber producing device.
 1042. The system of claim1041, wherein the collection elements comprise a projection extendingfrom the collection substrate surface.
 1043. A method of producingmicrofibers and/or nanofibers, comprising: placing material in a fiberproducing device, the fiber producing device comprising: a bodycomprising one or more openings and a coupling member, wherein the bodyis configured to receive material to be produced into a fiber; and oneor more outlet elements coupled to one or more of the openings, whereinthe one or more outlet elements comprise an outer conduit and an innerconduit, wherein the inner conduit is sized and positioned inside of theouter conduit such that material flows through the inner conduit and theouter conduit during use; rotating the fiber producing device at a speedof at least about 1000 rpm, wherein rotation of the fiber producingdevice causes material in the body to be ejected through the innerconduit and outer conduit of the outlet elements to produce coaxialmicrofibers and/or nanofibers; and collecting at least a portion of theproduced microfibers and/or nanofibers. 1044-1351. (canceled)